It should be illegal not to pay workers for the overtime they work. Many bosses love to hold up workaholics as shining examples of the desired corporate culture. Basically if you're working a 70-hour week for a 40-hour wage, your boss will love you. And why shouldn't they? They're getting an extra 30 hours out of you, and all you ask in return is to be allowed to do it again next week.
I've written about this some time before, and how it amounts to slavery of a sort, but now I feel we need to go one better. We need to make sure it is illegal for companies to give you anything less than your full hourly rate for time you spend over and above your normal hours. Hopefully the least that will occur is that companies will start realising the diminishing returns they get from overworking people.
Mokalus of Borg
PS - Of course it's hard to verify unsupervised work in some cases.
PPS - So there would be cheats, but there are cheats now, so how is that different?