If on the other hand, you think that since you've been eyeing a target everyone else has to stay away, I'd say go to the DA. The main arena is supposed to be a madhouse
That I agree with, and could only be supported by the fact that you have been in the area and really know that the guy is "eyeing". I have been there and have no problem with it. Also, in that same situation, I have had people say ... "Slappy, I'm coming to your right so watch out for killshooter" ... that is most appreciated when that happens.
If you have just arrived on the scene, and have no clue as to what had transpired previously, then a simple question ... "do ya need help" ... would still be a good thing to do IMHO. If I am not gaining, I will always say ... "go for it".