Where previously allowed, after market creation. A law introducing an exhaustive font whitelist that does not include comic sans would count. The ban does not have to apply to all legal documents (not even sure that's a well-defined term), but it should be fairly broad, not a policy affecting only a specific agency for example.

"Ban" should be fairly broadly interpreted: if using comic sans makes a contract non-binding, that would count.

If this doesn't resolve positively by close, I will spend a small amount of time checking how this should resolve, and give others opportunity to do so as well. If I don't find evidence sufficient for a positive resolution, I will resolve negative.