Hmm, OK, I was thinking I'd say something like, "On another thread it was mentioned in passing that prostitutes are often subject to public ridicule. This got me wondering about why this is so..." blah, blah, blah, haven't thought it through properly yet. I wouldn't name you, but thought it polite to check you'd be OK with it.
As to leaving/screaming, the difference would be that in the most common date/aquaintance/partner rape scenarios (we both know that stranger-in-the-alley is rare, though it does happen) the woman trusts, or wants to trust, the man. She is viewing him as safe, and the sheer shock when he rapes is enough to silence her, make her question her own judgement. For me, simply feeling uneasy would be enough to terminate the appointment, probably return my fee, and leave. I would have no emotional investment in "wanting him to like me".
I'm probably not explaining it well, but the dynamics are quite different.