@MartinSleziak Yes, that's possible, even with just a regular watch/blacklist entry regex. There are a few existing entries which do, effectively, that. It tends to be a bit computationally expensive in a regex, depending on how extensive the check is, but can be made such that it's not too bad most of the time.

@MartinSleziak Yes, in response to the wave of spam on [mathoverflow.net], I created a new Rule which looks for those keywords in titles on [mathoverflow.net] and [meta.mathoverflow.net].

@MartinSleziak Yes, autoflagging, generally, requires at least a couple of different detection reasons, if not a few or more. For this content, it would also be easily possible to set up a spam wave which targets it specifically with automatic flags, but I'd want to discuss it with at least one moderator on the site prior to doing so.