Staying on topic...I think a lot of the problem that people have is this...
501st costume requirements are based on the costumes looking EXACTLY or AS CLOSE TO the movie versions as possible. Which is understandable.
For a custom group, who makes the decision as to what to base if you are IN or OUT on? I think people are just afraid that because you've gone as far as making an approval process for joining, that the decisions are being made solely off of personal bias.
I don't know if that make sense or not... Now, I know that so far you haven't denied anyone admission. I think it's just the fear that someone may get denied.
Most people create custom mandalorians for either self-expression or because they don't have the time/skills/money/etc to create a movie replica costume. I mean, the 501st can deny someone because their costume doesn't look like the movie...that makes sense. But who is a single person to decide whether or not a custom mandalorian is "good enough"?
Would it hurt anything to allow "open admissions" on this group so that people don't feel that they are being judged on their work? I mean, if someone's costume doesn't seem up to par...let them join and then work with them to help making it better.
Again, I'm not saying that this sort of thing is happening. So far I haven't heard of a single denial of admission. But things like this can and will come up in the future. How will these be addressed?