Er, having your weapon drawn is synonymous to being in Battle Mode. It appears in the upper left corner of the screen when you do so. The battle music change is relatively recent (Originally, you only did get battle music if engaged), and was added specifically to give people a heads up to combat in their alliance rather than as a side effect of fighting mobs.

Do vultures suck? Yes. Are they doing anything illegal by standing around in a point of their choosing, doing absolutely NOTHING to hinder the fight or interfere with the combatants? No. Never. Not in a million years. At best it's rude, but so is /check according to some people =/.

I highly doubt this problem is as widespread as people are making it out to be, too. I have never, not once, seen a group sit around at a spawn point without pops for the sole purpose of stealing other people's NMs. Who the hell does that? It is a complete and utter waste of time unless you know you are dealing with absolute idiots who are going to be wiping/losing claim every pop.