Regarding 1, I have seen this happen. I used to work for a govt agency that made a mistake and overpaid a number of employees, who were allowed to keep the extr

Regarding 1, I have seen this happen. I used to work for a govt agency that made a mistake and overpaid a number of employees, who were allowed to keep the extra payment. I'm not saying that's the norm, but it affected a number of people and I have heard of it happening other times as well.