If people really don't like a day of cross teamers and bug exploiters... Then simply don't play on said day. Maybe half the lobbies can be anarchy and the rest aren't, this will make the people who need to keep grinding wins for leader boards or whatnot able to do it, also it would be cool if every non game defying command block was disabled, making it so you can mine blocks in the games and kill your teammates. Now some people might wonder what benefits are there?
The server can advertise anarchy day and might gain some people from other servers and even some might buy ranks, this can bring up holidays in cubecraft that are game specific, I am fairly certain no one is hyped for the new cosmetics and maps on the holidays, it is more like just adding new cosmetics and maps, there should be more in game differences, anarchy day, everyone has obsidian rank day, mineable lobby day, these days will bring lots of popularity to the server, at least for these days. A day where all the biggest you tubers will have content to the server spreading it around, yes it may sound stupid but cubecraft can benefit from days like this. P.s don't ban me from the forums for saying this.