Fatigue, are you saying that there are helicopter operators in the UK who bond you for three years (for an IR say) and, if they make you redundant, enforce the bond and make you pay the cost (or part thereof) back? I can't imagine that to be enforcable at all.
Spinwing, in your example, I would have thought that to be most unfair and contrary to an employment contract and again not enforcable.
I don't think the concept of training bonds is unfair at all but the terms must be fairly devised.
Cheers
Whirls