I know first hand of a few cases of non competes working (in France), and they all involved the ex-employer paying substantial amounts of money for the time the ex-employee was prevented from working for the competition.
Also known as garden leave. You're basically still 'employed' but you're kept out of the office with all access revoked. It's to put some distance between any time sensitive info from one job before you move onto the next. In the UK, I think the banks do this for three months.
The original employer must continue to pay a "significant" part of employees pay as long as non-compete is in effect and has to state clearly that they will do so in 14 days after the employee has left the company. Otherwise the non-compete is void.
Yes, which is a workaround as people get paid. If they didn't get paid it wouldn't work. As said; they are actually still employed but not working anymore.