Why not try a Tier system, if a client has 1 negative report they go onto your Database, if they get a second they go onto the database accesable by escorts, obviously if a client recives a very bad report he should go straight onto the escorts database.
You could also rate the report on a scale of 1 to 5,
1 being the lowest to 5 being the worst, i would imagine an example would be
1 - Very unhygenic
2 - Verbally abusive
3 - Verbally abusive and threatening
4 - Verbally abusive and physical contact
5 - Actual Bodily harm.
Just some idea's to get the ball rolling cause I have nothing to fear