Yes, police do enforce any company rules.  In other words, if this was a bar, your home, a business and you wanted someone to leave, you can call the police to make them go.  Its your property and you have the right to admit or not admit someone on that property.  Also this is airline security which enforce you know airline security.  Airline security is not part of United and their action actually is their own.  Since United is the one that called them it's still their fault that the incident happened.

As for the overbooking policy, you better check every airline because they all do it.  Federal regulations actually allows them to do it and regulate how they reimburse customers for overbooking.

He paid the ticket and United let him go on board. Everywhere else in the world, in case of overbooking it's the last arrived and not on board yet that gets shafted, never anybody that was already regularly boarded. He didn't board either sneakily or forcibly, United boarded him. United called the police, or the airport security, not to enforce a rule he violated, but THEIR violation of a deal they stroke with the passenger in the very moment they accepted to board him in exchange for his money.

It does not matter if you are on the plane or not on the plane.  Not sure why people keep thinking this is a distinction.  Federal regulations allows ALL airlines to bump passengers when overbooked even if they are on the plane.  This means that your ticket means nothing as far as you having rights to fly on any particular plane.  Usually all things get handled before boarding but it doesn't matter if you board or not board as you can still get kicked off.   

United called security after asking him to leave repeatedly.  Since United cannot enforce removal of a passenger, security was called because no matter what he was going to get bumped.  As I have stated, he played a bluff but once security came on the scene, the rules changed.  Now he was being asked to leave by security and by refusing the onus was now on him. 

On another issue, I am not even sure that this guy will be able to sue United.  Federal regulations allows airlines to oversale and bump passengers from planes so United was in their legal right.  Since it was security that removed the passenger which caused him to get hurt, then only airport security can be placed in the claim.  Should be interesting to see if a lawsuit gets filed and if United can be claimed.

United CEO apologizes again after it turns out the controversial flight wasn't even overbooked. https://t.co/J1BgxcWQII

— USA TODAY (@USATODAY) April 12, 2017

Where are those federal regulations, it's not in here
http://www.kcra.com/article/you-can-legally-be-removed-from-flights-for-these-reasons/9261454
Or here
http://onemileatatime.boardingarea.com/2017/04/11/united-denied-boarding-illegal/

It's time for the Government to up the bump price above $1300.

And that fact that United Airlines didn't even offer the maximum amount is effed up. Overbooking, trying to be cheap, and then calling security is three strikes.

Oh my. Heads will roll.

oh snap

I actually read the regulation and it states airlines can involuntarily force passengers from flights if overbooked.  It does not make any stipulations of whether they are on the plane or not which means airlines can do it at any point they choose.  Actually the only thing the airline has to do is first ask for volunteers before resulting to any measure they deem to use.  The regulations is pretty open on this part and it’s the discretion of the airline how they go about this policy.  Usually this all happens way before boarding but in this case it did not which of course is the problem that got United into this spot.  Interesting enough, when reading the regulations, it appears that United is the least company to bump you off a flight as all airlines have to report this to the DOT.

yeah it is absolute fucking nonsense.

United first put out some bogus statement where they claimed they 'overbooked', which was a lie. They had a full plane but not tickets sold twice. Then last minute had employees requesting (or a manager requesting) that they get flown to another location for work for the next day.

so United decides the right decision is to screw over 4 paying customers and take their seats to give to NON PAYING employees? are you kidding me? talk about the opposite of customer service. The hilarious part is that- A) its an airline, rather than put customers on another flight they could put their employees on another flight, and B) the distance the flight was going was drivable in like 6 hours, United could totally hire a driver to take their employees on the ground if it was that dire of a thing

In the end its mega disrespectful and unacceptable. The concept that a paying customer was supposedly randomly chosen to lose his seat to an employee (bear in mind an employee who wasn't needed for work until the NEXT DAY) is just absolutely absurd. And I say supposedly chosen because its fairly suspect to me that they just happened to choose two couples (this guy was flying with his wife for example).

Also as far as anyone claiming that there is a rule that they can take away his ticket- that's actually false. United has a ticket contract where they can cancel your ticket (generally for overbooking a flight) BEFORE boarding. the key word being BEFORE. There actually is nothing written in the ticket contract stating they can remove someone and take away their seat once they've boarded, and in fact there are standard airline organization rules that state that an airline must offer incentives (cash or otherwise) to guests until someone accepts in these instances. Of course United was cheap as hell and only offered hospitality vouchers (not cash) that no one wanted to accept since A) they weren't THAT much, and B) they can only be used for specific hotels and expire after a little bit

United almost certainly broke not only their own ticket contract and rules but ALSO possibly broke the law here. They didn't overbook, after the passengers had boarded they specifically chose to pick out 4 patrons to force off the plane to give employees seats. The fact that they later physically injured the 69 year old when forcing him off the plane just makes it even worse.

The guy 100% has merit to sue and will probably win. Its a terrible precedent to set by United and frankly we should all hope he DOES sue. overbooking is already a serious issue with airlines, but a case like this where an airline just arbituarily puts their employees first and says 'fuck you' to paying customers is a level beyond that.

its like Jimmy Kimmel said the other night- imagine you go to Applebee's, sit down, order your food, and then the waiter comes over and says 'sorry, some of our employees need your booth, you need to leave'. Its laughably bad customer service

the other patrons on the plane have told news outlets that the guy was being quiet and just not agreeing to 'volunteer' to give up his seat and that the plane staff were very condescending. That's also something hilarious with this story, that the CEO of United actually had the balls to say that when they needed to get employees on the plane they found 4 'volunteers'. As far as I know people are not volunteering when they say no and are then forced to do something

I mean in the end I think this bothers me most of all because of the balls of United- this is a paying customer and you end up getting him dragged out and removed to accomodate employees who DON'T pay for tickets and who didn't have any emergency to be at and didn't work until the next day? jesus. It was a Sunday and the plane patrons all likely have things to do and places to be on Monday.

an overbooking is one thing, as uncustomer friendly as they are, but when nobody on the plane wants to 'volunteer' to leave and you pick the answer to that as randomly picking someone and dragging them out of the plane to the point they bleed? just slimy. 

the good news is there are no doubt a million law firms that are lining up to represent this guy in court. United should've either not put their employees above customers in the first place, or at minimum not been cheap. If they had offered a few grand for disrupting someone's schedule (somewhat majorly as I've heard the next flight wasn't until the following day) then someone probably would've accepted their offer and 'volunteered'. but, nope, they had to be ass holes and drag someone out of their paid for seat. When a legitimate paying customer is getting dragged off a plan when there's been NO doublebookiing that suggests an extremely poor state of things for that company's level of customer service