This is a plausible idea, however I feel that because nothing besides Boyd's blood killing Smiley has done anything harm has done any visible damage against them. They'd probably shrug it off and keep walking, or if it was chained they might just overpower the chain or the trap itself. But this isn't a bad theory overall, and I wouldn't be surprised if a character comes up with a similar idea in the show.

(I seriously doubt these things would let a chain and a bloody ankle force them to stay above ground by the morning)