They come too early. On my current fort I managed to move everything to the other side of the river to avoid people harassing cave creatures. I was successful, and none followed us. We even managed to build and unbuild the bridge everytime we had to let migrants in. So, feeling free of the menace from the cave-people who didn't even have a cave any longer, I started building walls around my camp, leaving the river section for last. Well, winter came, and the river freezed, for a very short time. Three niths made it into my camp nevertheless, two picked the fight with the wrong opponet and got eaten by a drowspider, the third killed my warband marshal, who had a bloodsteel scourge. The fight went like this: Miss, Counterstrike Miss, Miss, Counstrike, Niths shatters Marshal's finger, Miss, Niths scratches Marshal's brain out. I couldn't have prepared a cage halley by that time, especially you consider the huge number of cave creatures. Hell, it's like a David and Goliath situation, where David comes in Goliath's home, wanders around for a time, then breaks all his bones and shatters his skull with Goliath having no way to oppose. AND IS STILL DEPICTED AS A NICE, VERY FRIENDLY GUY.
Anyway, talking about tokens, would an evil pet go after "benign" creatures?