The only explanation I could really get out of anyone is that when people are rushing ahead to do the exploration tasks, they have an "unfair advantage"? Like, I think one of the examples they gave was for tasks where you have to find a certain Pokemon in the shelter. People who know about the tasks beforehand will know to go find two Houndour from the beginning so they'll hoard all the Houndour early on. But that makes no sense. People are going to take all the Houndour anyway. At least people who take them early might release them by the time people doing it the "normal" way get to that task. Otherwise, maybe they'll breed them in preparation for it so that by the time they get to that task, they've saturated the shelter with Houndour eggs. If anything having people doing tasks early is just better for everyone.
~_~ But it was more the way they handled the situation than the situation itself that bugged me so much. Sooo unprofessional.