Alright, so I tested this out a bit. Every time I got knocked down (or surrendered, since I typically died before they took down my stamina all the way) I was sent to prison. Tried it maybe 20-30 or so times, and ended up in prison every single time. When I aggro'd the guards in the market and got knocked down or surrendered on the other hand, I got a dialogue where a guard called for a slaver, and this also happened every single time, though I only tried this maybe ten times instead. That dialogue did absolutely nothing though. Lona just woke up on the spot with more stamina and lowered hunger as if I had slept outside like normal, and was never actually enslaved.