Today's Wall Street Journal had an article about "why they stay." Mostly it has to do with work contracts that have very punitive clauses if the "guest worker" goes home early. I guess if you sup with the devil, you'd better use a really long spoon...
Maybe these punished Americans can be a PR nightmare for the Sodis (deliberate) back here in the states.
The "guest worker" goes home --- loses a lot of money, the "guest worker" stays --- loses his head. Some choice. The excessive love of money can be a bad thing.