I don’t know if this has been talked about yet, and not totally relevant to an an actual “bot-farm,” but what the hell.
All of the stats sites including join-lemmy, gather self-published info from instances.
It’s pretty trivial to create an instance, federate, and get to the top of all of those lists in a matter of a few days, without creating a single user.
It’s not going to fool everyone, and whoever admins those sites might remove those instances, but as it stands right now, if I wanted to funnel a bunch of refugees to an instance, that’s exactly how I would do it.