In starting this thread I realise I may be stirring up a Hornets nest, but here goes.
Have you as a model felt that the person who booked you, and possibly paid you, could be working out some deep psychological hurt or problem?
Have you as a photographer felt that the person you are making images of is doing so for some deeper reason than 'fun' or to make money?
As long as nobody suffers further physical or psychological harm, does it matter?