even so let's say you programmed a trigger to make a double strike, it would take great skill and internal clocking to make the strikes fit in with the tempo structure of the song. on my roland kit there is a fun little kit called 'drum solo'. when you hit a tom once it fires four times rapidly. sometimes for fun i play it. to make a continuous single stroke roll takes some cool minded skill.
that said i very much doubt joey uses anything like this. i have read several articles and interviews on him and my roady is a huge fan. so i have seen nearly every slipknot DVD especially the ones with a joey cam. believe me he doesn't use double triggers etc.
ill take your word for it, but triggers still rub me the wrong way