Best case scenario, they say, “sure, go ahead” in a timely manner. Then, you can have the event, maybe for a few years, but the moment they feel that it’s one dollar more profitable for them to run it themselves, or you decide to promote something the slightest shade off message (say your charity for one year becomes the EFF), they swoop in, end it or decide to take it over, rendering your hard work and the sense of tradition meaningless.
Much more likely, their e-mail gets no response at all, in which case either you do the event anyway and are in the exact same situation you’re in now (with the added complication that in any legal action that might come against you, they can point out that you asked but were never given permission, bolstering their dubious claim that permission is NEEDED), or you don’t do the event, in which case you’ve wasted time planning (and you’ll never know if you’re GOING to get a response until the time for the event comes) and a fun thing that helps others doesn’t go on.
Or, still more likely than a yes, you get a no from some drone who’s job it is to refuse everything people to ask. Same thing, only worse.
There is no win here, short of the corporation deciding not to be asshats. There’s only ways to lose less.
If you ask me, they did absolutely the smart thing by not asking permission first. Corporations are sociopaths, and it’s best not to deal with one unless you absolutely have to. And if you’re going to, you might as well use their tactics: a cold cost/benefit analysis says it’s one situation where, assuming the event is one you want to do, it’s better to ask forgiveness than ask permission in advance. Or better yet to not ask forgiveness either, just do what you’re going to do and ignore them unless they force you to do otherwise. And when they do, you have the small chance of public outrage when the corporation cracks down on people doing something for fun and charity.
But it’s nice to know you have no sympathy for people being charitable, and apparently reserve all of it for an entity legally required to pursue maximum profit at all times, at all costs.