If people like the option, you could just amend it by saying:
-For the schemes Team17, BnG, Elite, and Hysteria, if one team requests it, the host must use a unique (never played by himself or his clan) random map generated in the in-game editor for that specific game (so you must left click on a map template until getting a map you like). You may edit the map with the in-game editor if such editing is obvious, though the map must still be unique, and no using .PNG files.
And I think it would be useful to include shopper and roper. There should also probably be a rule regarding map choice if the host refuses to budge, like having a moderator host, since the hassle alone would probably force people to come to some agreement.