I've come to hate BST's with a passion all over again. Long long time ago they would wipe out XP parties so they could continue soloing in a camp (we tend to kill their pets for XP). Now their just being annoying inside dynamis and doing stupid sh!t like soloing 4+ EP's at the same time. So I take great pleasure in disrupting their activities, especially on BLU where I can AoE the crap out of everything with fast casting spells.
If a BST is fighting one mob and doing the dyna thing then I leave them be, if I see them trying to fight a whole slew of mobs and going down the line procing them, I'll start using WoR and BT on their mobs.