In short: nothing.
As an IP owned by Columbia Pictures and Sony Pictures Entertainment, Ghostbusters is not something anyone has the right to utilize for monetary gain outside of those companies. IE: you cannot profit from being in a Ghostbuster uniform unless you're hired by one of those two companies. Here is the big misconception that keeps appearing:
- Regaurdless of charitable and altruistic aspirations, you are never, under any circumstances, granted the legally protected freedom to use the Ghostbusters IP in order to raise funds. Columbia seems to turn a deaf ear to the actions of franchises as they tend to build good will towards the Ghostbusters franchise, which is awfully nice of them, but they are allowed at any moment's notice to disband a franchise, website, etc as they see fit.
Selfish acts, such as charging for appearance fees, can easily ruin things for everyone. While it isn't an immediate threat, keep that in mind if you ever consider pocketing money or requesting money for an appearance.
Raising money to pay for a fan film or prop and claiming it is a charitable endeavor is, firstly, just selfish and a misplacement of intent. You can certainly raise money for a fan project, as the fellas behind Return of the Ghostbusters, Ghostbusters: Generation, and GB SLC have done for their respective fan films, but none of those projects claimed to be charitable acts that would somehow benefit a cause other than their own creativity & the fan community at large. Those people didn't say "Hey, pay for our movie- it's for charity!" If you plan on becoming a Ghostbuster or a franchise in order to raise money for various benefits, you should never assume other people will pay the thousands required to outfit your team with props. That is just downright silly and borderline sociopathic.
DOs and DONTs, is an attempt at explaining the legal-side of the Ghostbusters franchises. If anyone has anything to add (or fix, as I am in no way a legal expert) please feel free to do so.