There are a lot of communities that were created in the last week but never had any kind of interaction or their mods never started to post to attract people (they don’t even have rules or a description).
Will there be some kind of cleanup or will it stay there until someone asks to take over it?
I think OP is moreso referring to the actual communities than users themselves. Parking empty user accounts is one thing, as they exist but don’t really cause any issues, but empty communities may lead to unmoderated places, a lack of rules, etc.
I do imagine with the influx of bots those ghost accounts could get purged though. At least using them once to have some traceable account activity would be enough to have them persist through an initial wave.