Note, I never really played P99 to any gear camping levels but how is this any different from EQ back in the day? Plenty of times when I can think of calling into guild chat that I was planning on leaving X camp and invited anyone in guild to come take it from me. You owned the camp, you can invite whoever you like to join you. If you leave shortly after... that's just how life went. No random guy could just show up and demand it, regardless how long he sat on his ass watching you.
(I am thinking everthing from AC camp, VP key medallions, to loot mobs all worked this way)