with Roelkin, I pretty much *never got caught stealing from PC's, ever. Rarely, I would step out of the shadows but for the most part I could spam steal on someone without roots/area attack/fog and go afk, not that I did, but I could've.

Stealing from shops, that's different, and the races of shoppies and types of shop comes into factor.

This is ofcourse, my opinion and personal observation with only one city thief, but I would steal from anyone and everyone without a blink of an eye.