Maybe the detection (or at least, narrowing down who might be a botter) is the WoW game settings? I won't name everything but for example, if a player has a match on some very specific settings all being active/true (using 32-bit WoW client, click-to-move enabled, and some other settings that seem to always get changed by HB)
Not technically possible, since virtually millions of people do use 32bit, low graphics and CTM, yes millions still do use CTM, like it or not.