Cool thread, I started several games in the past two days or so for the sole purpose of playing the beginning and practicing stealing workers.
I used to just take two from the nearest CS then make peace; the first one that pops at turn 20-25 and the one they make right after. Annoying though if a barb rolls up on their land, or they decide to make a boat instead of the second worker.
I was inspired by watching LPs to try taking them from other civs instead. On Deity, you can start getting workers basically as soon as you find a civ, which is way earlier than waiting for a CS. I saw Moriarte in a game have two workers already improving his tiles on turn 17. Yes please, I want some of that in my games, too.
I've haven't seen a civ move a settler without a warrior escort so IDK bout stealing one and glitching its AI. The first lesson I really had to teach myself about getting workers was stop being greedy and make sure I actually can get the worker and my warrior/scout both out safely. It's definitely worth waiting a turn or two for a worker to get in a vulnerable position, and it almost always does.
The first game I had it working really effectively I had 9 or 10 workers from Austria by the time I was starting to plant cities @ turn 45-50. I pillaged a farm then sat 2 forested hill tiles away with my scout, and they just sent worker after worker over to repair it. I ended up bringing a warrior down to fortify in city range and eat shots, the scout wasn't getting enough heal time between workers showing up. After that it was like a lightbulb had gone off in my head. I haven't ever taken that many again, but most of the time I get 2-4.
Occasionally though, it seems like civs are too far away, maybe through a lot of rough terrain, or the real killer, a barb camp spawns right next to my steal spot. I suppose then I'd have to settle for a later CS worker or two.