you have to have a special license to order some of the herbicide that's used in those rigs. but not many people have it. so sometimes a guy who may or may not be MY OWN FATHER will order some and leave it out on his trailer and tell his bud about it and then it disappears overnight.
also a special license to buy the tranquilizer poison stuff that you dart bulls with to knock them out when they are getting all rowdy and won't do what you want them to. then you give them the antidote to wake them up. it's irl secret agent movie stuff. but it'll kill the crap out of you if you jab yourself with the dart so it's good that you have to have a special license or whatever. so my dad will sometimes get called to come out and shoot a poison dart into the ass of a bull and knock it out.