the fact that you think referee are actually here to referee is cute.
If they caught a cheater, it wouldn't do any good to either the player (obviously), the org (obviously), the tourney organiser (match cancelled, fucking up the schedule, losing air time etc...)
they referee at low tourneys but unless a known pro player starts spin botting, i doubt they'll do anything about it.
You might notice it but pros usually have an aim key, I advise you to watch a whole match following only one pro and keeping his pov from begining to end, you'll see that those little flicks through the wall that could be just luck if they happened only once, happen quite often actually. they create a pattern and there is no doubt that some pro players have an aimkey