Remember that PS & FTP don't write the checks themself. They have a payment processor do it for them and the checks are drawn against these processors. In the past there have been incidents where the processors have had their problems with the US gov and checks have indeed bounced (including PokerStars
cashouts). So far FTP & PS have made good on all problems in this area, it would be suicide for them not to.
Yeah it sucks when it happens to you but work with FTP and they will make it right in the end.