Okay, we had a "small" admin meeting and kind of talked this out. We didn't establish rules, but we've come to a general consensus:
Mcmmo skills do NOT matter in fights. There are many documented battles in which someone with an extremely low mcmmo stat beats someone with an extremely high one. Because of this, you should not be prejudice to someone based on stat level rather than their true skill. Yes, it is annoying to have people challenge you, but as a gym leader, that is your job. Just because people ask help from me or other admins every waking moment on the server does not mean I say no to them because their new.
Sure, maybe they will come one the server for 10 minutes and never come back again, but I do my job because I like it and in the more professional way, it's my job. I only hope gym leaders have a similar feeling.