What I find convenient about admining a room is that you can easily block users and then automatically delete their message history as well, so since you can undo whatever they do, even if they are able to join and succeed temporarily, in the long term their efforts amount to nothing.

You also have fine-grained control over permissions so you can even make it like IRC or XMPP where rooms with severe moderation problems can be made so the default role when a user joins does not allow them to send messages until you give them voice, so to speak.