Regardless of the rights and wrongs of this scheme, for those thinking of applying make sure you're clear about what happens to your 18k in the (unlikely) event you don't meet the required standard. Are you employed before you start? Is there a money back clause if it all goes wrong and if not, are you willing to take that risk? It's a lot of money to invest without guarantees.
BA is not the only option either, all the airlines below hire modular pilots with either a free rating or a bond with no upfront payment. Paying for a type rating doesn't have to be the norm.
Jet2
Flybe
BA Cityflyer
Aer Lingus
Loganair
TCX / IAGO
In short, do your homework
