Despite me being the "Botgirl" I do not really like autofollow-bots. It reminds me too much of hellbird scraper bots that would just harvest and pilfer data for the benefit of others. Especially the bots that brag about how many people they've auto-followed.

Social networks, even/especially federated, should organically grow. This is only my opinion (and others may share similar). To me, it defeats the purpose of the "social" aspect if one just forcefully follows everybody they can via a bot/script.

Also, so far it doesn't seem that bots scan for content, so you may also end up with potentially unwanted instances/people/topics in your federated line, due to these.

Opt-out blacklists, like a certain bot I have seen, are also annoying because they expect you to message the owner and ask to be blacklisted. This... reminds me of opt-out sales / spam email. In my eyes it is a very unwanted thing.