I don't condone poisoning in any manner. It can't be targeted at a specific species. Any other animal can get into it with the same results. Eagle, bobcat, fox, dog, raccoon or even bear can get into them.
The govt trappers use the critter getters around here from time to time. i don't like it because my dog can get into one and have it go off in his mouth just the same as a coyote. For those of you not aware with what that is, it is a trap with a bit of fur on it that when pulled on it shoots a shell loaded with cyanide into there mouth. They put up flags on them to warn people, but flags can disappear too.
They don't work either. Last year Cmiddleton and I hunted right near one and we called in a coyote not 100 yards from it and shot him. When we went back to the truck there were new tracks right past the truck and the trap on his way to the call.