4/5. Breaking roads won't be enough since smuggling can occur in ports, airports or railways. Hills ? They can still be destroyed or one can go around them so it's pretty clear that Ireland will need armed guards to prevent breaching especially when there's not any other realistic solution in place with over 200 crossing points. Don't worry about the security of the UK, in fact most of the arms that the Irish paramilitaries procured were from Syria when they brokered a deal with colonel Gaddafi to have them shipped directly to Northern Ireland and I doubt Ireland is keen on letting their civilians have military grade weapons so the potential for arms smuggling through the Irish border seems remote. If the worst comes to it then the UK will just increase the police force to control any violent dissidents and that's a realistic option since it's a lot easier to enforce authority over a smaller area ...
@Bold Or Ireland can just leave the EU single market if they really care about Northern Ireland ...
As for the rest, I don't think you understand the UK very well. Northern Ireland is not even in the same situation as Scotland since the former requires that it's own Secretary of State to call for a vote. Despite your constant fear mongering though the UK is a more functional union than the EU is and Scotland's own nationalist party (SNP) got decimated in the last general election (they lost 21 seats) AFTER the referendum so the Scots clearly aren't all that impressed with the EU to dump the UK ... (the strength of the union will be tested again during the May local elections in Northern Ireland and I suspect that the DUP will make some gains since they secured a billion quids in funding for Northern Ireland in a coalition with the Conservative party)
The ports in Calais and Rotterdam don't block goods coming from other EU members so the if the UK has a backdoor then the same applies. While the UK's own domestic production may not be able to undercut the EU, I'm pretty sure their imported goods will and trade surpluses will start to build up for the UK ...
It's going to be a day of reckoning once the EU and Ireland turn against each other ...
4+5: Anything that arrives in a port or airport in Ireland gets checked by customs, even if the goods come from the EU. The reason is that ships are huge and and not all goods are guaranteed to come from the same source. Also, in case of fresh foods and livestock, everything needs to be controlled no matter where it comes from due to hygiene and disease prevention (that's basically true for every island as they get counted as a whole in these scenarios, but apart from Ireland there are just a couple more islands where it applies, Borneo, Cyprus, Haiti, Papua and Timor are the only other ones that come to mind).
Hills can be destroyed... but having the UK destroying hills in Ireland would be qualified as an invasion, as they have no right whatsoever to be there. So forget about the UK even trying to do that (in case you didn't understand, just on the Ireland side would the road be covered with a hill to male it impracticable, unless the UK would want to do the same on their part of the road).
In other words, roads will be the only viable points of entry for your smuggling. You can always try off-road, but since the Trucks are not built for going oof-road you'll have to do it with SUVs - and they transport considerably less than a Truck. So unless they smuggle high-value contraband, smuggling by SUV will only amount to a drop in the ocean.
@underlined: You got a source for that? Also, you think that's still true almost 10 years after Gadaffi's death? Besides, it doesn't need military grade weaponry for guerilla tactics, plus most civilian versions of military guns can be converted into military grade by halfway skilled gunsmiths. But in any case, gun smuggling was just meant as a counterargument and showing that smuggling can go both ways. You didn't understand that, you failed the test.
@bold: Or UK lets Ireland reunify if they care for the inhabitants of Northern Ireland. Problem solved
Me, fear mongering? You are the doomsayer here, telling how supposedly Ireland and the EU will go down in flames. That's the hypocrisy of most Brexiteers by the way as far as I found out, as any Brexiteer I met or talked to acted like doom and gloom would hit everybody, but not the UK if they leave.
@italic: You seriously need some lessons in macroeconomics. I won't even try to teach you there anymore, having tried the last half dozen of posts or so.
About the last line, oh yeah it will. And since the Last Judgement is based on the thinking that the dead will raise beforehand, it will only happen after a Zombie apocalypse, so basically never
The Nintendo eShop rating Thread: http://gamrconnect.vgchartz.com/thread.php?id=237454