Instances, of course, have some bot-mitigation tools which they can use to prevent signups, etc.
However, what’s stopping bots from pretending to be their own brand new instance, and publishing their votes/spam to other instances?
Couldn’t I just spin up a python script to barrage this post, for example, with upvotes?
EDIT: Thanks to @[email protected] ‘s answer, I am convinced that federation is NOT inherently susceptible, and effective mitigations can exist. Whether or not they’re implemented is a separate question, but I’m satisfied that it’s achievable. See my comment here: https://programming.dev/comment/313716
This is the how most instances operate at the moment. Some instances have an extensive blocklist, others have none or almost none. Whitelisting by default would be a bit antithetical to the idea of a federated social network, as any automated system for such a thing would still be able to be abused by the sort of person willing to set up a whole server just for spam or whatever and any manual system means you would probably end up with a bunch of small islands of federation and/or new instances being potentially unable to federate at all.