(This is a duplicate of a post I made in the "Slavery Ideas" thread in the New Features board, but it applies to this thread too. If you've already read it, feel free to ignore it.)
Honestly, I like to look at it the other way around - not "let's findways to penalize slaves," but instead "let's find ways to make freegirls better."
I mean, you have to figure that in acity like Crossgate, which is explicitly stated to be run by criminals,the rule is basically "might makes right;" slavery has to be incrediblywidespread. It should be the norm for a brothel owner, and a free whore should be a rare thing indeed.
Sowhy free your girls? Well, for one thing it makes them very happy -they see slaves every single day, and get reminded that their livescan't be all bad - at least they're not slaves, right? - giving a daily(small) bonus to Happiness and PCLove. For another, they know full wellthat they have to do good work in the brothel, or elsethere's always the threat of being enslaved and sold off; they shouldhave a lower chance to refuse to work. Also, their greater freedomshould make the Free Time "job" more effective; for them, it really isfree time, as opposed to a slave's free time, which is still withincertain strict limits imposed by their owner. Maybe only free girls arepermitted to carry weapons, too?
In Crossgate, slavery should beeverywhere. It's the default. There's no sense in sugar-coating it, Ifigure. so don't penalize it; just make the alternative moreattractive, nice little bonuses in exchange for the loss of completecontrol.