I understand that banning a user prevents them from submitting their own runs to the site. Is it acceptable for a moderator to submit runs for the banned user if they achieve a record after being banned from the site?

Per the site guidelines, and a few occasions where I've either seen it or had to approach that problem over the years, it's up to the game moderators.

However, that doesn't (or at least shouldn't) include letting banned runners evade their ban by submitting all of their records to an alternate account.

Ah alright, thanks for the response. I must've missed that line when I went looking for it in guidelines before. Much appreciated.