While I was leveling on Mal'Ganis server alittle while back I came across so many alliance, i was horde at the time, that didn't bother me as long as I didn't bother them. Help lots of times we would all be just questing in the same area and just let each other be. Sure every once in awhile some asshat would come along and kill ya, although it always seemed to be someone who would undoutable win the fight, as in someone 10 levels higher than you.

My take has always been, keep an eye on them just in case but otherwise I let it be.