I don't know much about the UK or Norwegian tax authorities, but at least with the IRS you might have just gotten lucky. They only have sufficient manpower to g

I don't know much about the UK or Norwegian tax authorities, but at least with the IRS you might have just gotten lucky. They only have sufficient manpower to go after a small percentage of questionable returns, so even if you make a lot of mistakes on yours (or evades taxes), there's still a good chance you won't get audited unless you're a big fish.