DK,
As far as I'm aware, it is illegal to bond anyone for training. Especially 'non-reducing' bonds. Airline Bonds are more of an agreement that they have produced to protect themselves against pilots 'getting their rating and runnimg'!!!...
As already said, choose your airline carefully, DO NOT SIGN UP TO A NON-REDUCING BOND!
I have no problem siging up for a bond in principal(especially if it is an airline I have wanted to join for some time and intend to stay at!), but I think these 'Schemes' that many of the lo-costs are making non-type rated pilots enter into are nothing short of a SCAM!(Reduced salary for 3 years etc...) Someone somewhere is making a lot of money out of you. The training provider it would seem is in cahoots with your airline, and between them they are making a handsome packet, let alone the money lender, who BTW is usually a highstreet lender who gives you the 'going rate', charges you £100 set up fee, then when your reduced salary repayments start, you the lender pays the Interest back every month (around £90 pmonth).
So all in all, entering a 'Scheme' isn't all it seems. Whatever happened to good old bonding? You leave you pay back what you owe.....Nope, some bean counter thought aghhhhh we can make a buck or tWO here out of our own staff

DISGRACE!!!!
I don't agree with not paying back your loan though. You enter into it, you pay it!