Eh.. since I'm still questing, I don't bother unless provoked. Usually it's more than one lvl 70 that provokes me, and when that happens, I fight back with the lines of Brad Pitt in The Mexican going through my head..
"Give me a good reason why I shouldn't fight... If it comes to that, someone will leave here missing an ear or not being able to fuck any more. One reason, now that you let me know what you think I'm made of."