If a toon was going to:
xxx,yyy,zzz
yyy,zzz,xxx
zzz,xxx,yyy
xxx.zzz.yyy
yyy.xxx.zzz
zzz.yyy.xxx
and then for the next.... however long, it does it over and over and over. Goes to those EXACT spots time after time (click to move is gay, one flaw of HB), it doesn't take long to have enough "proof".
This is why we REALLY need that idea of slightly randomizing hotspot numbers to become a reality, so that it never repeats. But even then, if they had a log of your movements, and put it into a "simulator" to see your movement path, and see that your going around in circles in pretty much the same way over and over, your still gonna get banned. Wouldn't surprise me if blizz has invented such a simulator, where they just copy paste someone's pathing history and it shows them lines across azeroth (think ROUTES addon lines) where the character has been. Same spot for hours? = Ban.