I'm all for drive by buffage. Do that often on my Kin or Emp.
Someone pulling a mob train after them, I'll check their health before I do anything and the level difference between them and the mob. If they are on their last gasp, I might step in and delay/ambush the mob. It could just as easily be that they are running a damaging toggle and passed a mob on the way to their destination, even low conning mobs will chase someone after that and they may choose to ignore them and keep running.
Someone pulling a Leroy Jenkins though, that can be a learning experience for said player, don't bite off more than you can chew through.