I'm not a professional pilot, but this is one of the fora to which I'm invited. I'm also at UTC +12.
I enjoy the identification competitions, almost exclusively as a spectator sport though I did once win as the first to i/d a Breguet Deux Ponts--by the standards of recent competitions a thoroughly common and indeed banal aircraft. What stops me participating is first a lack of knowledge, and second the fact that the challenges are solved so quickly, so much so that it's not the time zone difference that counts, but how many hours in the day one spends watching the thread. I observe there's a relatively small list of regular players, but this is not really a problem for me as I'm interested in the aircraft, not the participants (sorry folks, I'm sure you're all fascinating IRL).
If anyone felt there was a problem, though, I suppose there could be a rule that no entries were accepted until a certain length of time had elapsed since posting: but I don't know how you'd enforce that, and I'm not proposing it, just mentioning it as a possibility if people feel there is a problem.