I know little of REX other than what I glean here. However my impression is that if you jump bond they will hunt you down whatever the legal cost to themselves. In the greater scheme of an aviation business 100 grand or even double that for lawyers and court appearances is nothing. They are fully aware that the 'law' has financially broken more than one individual trying to defend a position - whether morally right or not - and WILL call your bluff. To do anything less would be loss of face. Ask anyone who ever tried to duck out on Singapore Airlines what happens to bond-breakers.