I admit I'm greedy when it comes to this. If I got an area to myself and someone comes along, I'm not going to leave anything available if I can tag it first. I hate having to farm things and would much rather finish things as soon as possible, and competing for spawns just slows things down.

However it also kind of goes both ways for me. If I arrive at a farming area and someone's already there, I'll go look for some other place to farm since I wouldn't want to slow down their farming.