If you are in a Bond payback situation , as long as you make any attempt at paying it back , say a tenner a week , then no court is going to nail you . After all , you are not refusing to pay are you ?
Its a bit like the difference between tax avoidance and tax evasion , pay a little , pay anybody , but don't pay a lot.
I once worked for an airline that changed the notice period to 20 weeks ( approx 5 months ) to stop people moving on . An industrial lawyer pointed out that if you were paid monthly then you only needed to give a months notice and so on . When some tried to leave and gave 3 months notice which is what their contract said and the company threatened to sue , the airline soon backed down when lawyers were queuing up to take the case on.
I think a lot of people do not understand their rights and are intimidated by their contract . Whatever your stage of aviation , it always pays to have yr contract perused by an employment lawyer , does not cost much.