As far as I am aware, the !roll command is used to determine who is going to be the host in a #multiplayer match. using the !roll command anywhere else creates needless spam, and should be removed from most channels, especially #spectator.
Moderators are aware of it and I doubt the !roll command will be disabled (same goes to other commands). Just report them by typing: !report username reason
Example: !report This_user is abusing the !roll command