Dear lord, how the hell is this even a damn debate?!?!?
Have separate events for each: Custom LEGAL, and Custom BANNED
It's not that hard really. This would solve the logistics problem as well as any balance issues.
You have the players that care about customs unlocking them in preparation for the tourney they want to enter,
and the people that don't care entering the regular one. We already have an example of part of a move set
causing similar controversy within the Smash community: Wobbling. What did we do? Have Wobbling legal
for some events, and Wobbling banned for others. To this day, we still alternate Wobbling legal and Wobbling
banned, and I say that's a healthy attitude to have towards customs. It will be a different game after all,
with a different meta game.
Custom move sets have never been done before, so they need to be handled differently.
You can't keep applying the same tired logic to a completely different subject.
So go ahead and have your BANNED events for now, but please, PLEASE, set up some custom LEGAL
tourneys. People will know in advance what to have unlocked, and the TO and his staff can prepare
accordingly with the setups beforehand, and with some on-call 3DS attendees. (double as judges to check equipment, be available for double blinds, etc.) You can even have players RSVP with their request for custom move sets in advance, or have them bring their own setup. If they do not, they will just have to deal with the default move set, which isn't a terrible loss for a lot of characters.
tl;dr
The point is, there is a demand for Custom LEGAL events, so it is our responsibility as the community to step up and make it happen. We don't have to submit to having nothing but Custom LEGAL, but we shouldn't shut ourselves off from something the community could grow from.
In other news, I am borrowing a copy of smash 4, my 3DS friend code is 3411-1766-3642, and I will be online tonight.
Good day, Gentlemen.