Is it possible to notify the room of guideline changes using an audit message?
Maybe a short message posted by the room owner/moderator who made the change or Stack Exchange.
Example:
This room's guidelines hashave been updated by (username), please. Please view the changes at [link].
or if the audit message is to be posted by the user who made the change:
This room's guidelines hashave been updated, please. Please view the changes at [link].