This meta post Flag abusive users suggests to flag abusive users by flagging one of the posts, so that the mods can deal with the problem.
However, on The Workplace (where I am a moderator), we had a situation where one new user made rude/abusive suggested edit (specifically, he changed the question title to include "because I'm an idiot"). The user has not made any posts (questions/answers/comments).
In this case, some of our moderators are regulars in the site chat room, so some alert users pinged us there, and it got resolved that way. However, this is more of a workaround and doesn't work if moderators don't hang out in the chat room.
What is the preferred approach to handle this situation?
One alternative I could think of is the alert users could custom flag one of their own posts and post a link to the abusive suggested edit to bring it to moderators' attention. This doesn't seem to be a clean solution though.