This is a simple (and probably terribly coded) plugin that will detect non-opped players when they switch from Survival Mode to Creative Mode. The gamemode switch is canceled and the plugin bans the player, as well as their IP.
In addition, when a player joins the server their gamemode is checked for Creative Mode. If they are not opped then they will be banned (both username and IP). This is useful if players illegaly obtained Creative Mode before using this plugin.
This plugin is mainly for FTB Ultimate.