I'm really glad to see some intelligent debate on this for once (usually im flamed for being "anti-wanabee"
).
BALPA should do something because it does have a impact on new hire T+C's but in my experience they seem fairly disinterested or ineffective with even small airlines so I doubt we will see any action from them.
Paying for a TR is different in many respects because it is all training and the TRTO (whether its a dedicated facility or part of an airline) is offering a service. As long as there are freelance pilots, we will need TRTOs.
However, the question should be asked whether offering a 757/747 rating to a 150hr pilot is ethical? What exactly are the chances of said pilot finding employment? From my experience, not so good. Hence these hour building programmes springing up (lets be honest, its really not line training).
I think they are getting around employment laws by calling it line training when its blatantly not.