99% of the time, the dps and healers are behind me or they stop before they get to the mobs so I can grab them. I usually give the dps the benefit of the doubt, there's been times on archer and mch I've accidentally pulled, or Jumped the gun on drg. If it's an ongoing issue, I'll say something about if they pull again, they get to tank the pack. If they steal hate, I see if I'm doing something wrong or missing something first. Then I start marking mobs. If they're attacking number 3 while I'm working on number 1, I'll flash/overpower/unleash/voke. If they keep at it, it's their mob until they die or we get to it, or it goes after the healer.

As far as the threat gen thing goes, most are more concerned with their combo timers.

I really do hate it when they run from me, though. I often tell them at the start of dungeons and bosses that if they get hate, just bring it to me and I'll take it.