What really gets my goat is when I find myself having to, due to time restrictions, decide between going to event spawns in location A, B, or C.
I decide to go to B, the dinosaur despawns. Well, crud. I already wasted time and now I have to wait for not only a solid spawn but also the OPPORTUNITY to GET to said spawn.
Please put despawn (and respawn) timers for event spawns. It would save so much frustration.