Because whenever you see people doing a wheelie, they're probably not actually doing a wheelie. This is because most Nintendo online games are not using a main server, but peer 2 peer play. Since that's a very unreliable way of hosting, all online gameplay is actually calculated by the Wii's processor instead of it acually displaying what's happening real-time.

In other words, whenever you see somebody do a wheelie, it's your Wii calculating that that person is probably doing a wheelie at the time. This may not be true, or you bump him and the Wii needs to calculate you bumped him, therefore you won't see it happen right away.

Summary: Wii's online is really, really crappy. It's worse than the Doom on PC games back in the 90's.

EDIT: This is why New Super Mario Bros. Wii probably really can't go online, simply because the Wii's processor is not powerful enough to handle it.

Not when your VR is on the line.

Also my VS VR is a very respectable 9082 now because of a hacker.

The good ones are cool but the bad ones are annoying as hell.

I agree with this.  I'm somewhere in the low 9000's now and because there are relatively few players in Australia i often get matched up with a race full of people ranked 5-6000.  Add a hacker to that race and a single last place (hackers often target the best players) will cost you 400+ VR points.  You can lose them in one minute  and i couldn't tell you how long it takes to get them back.  Disconnecting gives you the same result and since you can occasionally still beat hackers i'd rather try my luck and then look for a new race.