I agree with an earlier poster that the way to stop this is to make the general fare paying public aware of the P2F schemes.
BALPA, Ministers etc. Already know about it and choose to do nothing. What it needs is for people to actually stop using certain airlines because they are crewed by someone who has paid to be there. Im really suprised one of the big newspapers hasn't picked it up already. I only hope it doesnt take an accident to happen before this comes out.
What really suprises me though is the fact that none of the airlines that choose not to use P2F pilots isn't using it as a marketing tool to discredit the airlines that are.