How does it shadowban exactly? Is this proven/tested?

That's a good question, I guess we'd have to rely on curation for that part, if someone opens up the twitter link where you first used the hive tag and see that you went on discussing it for many tweets, etc, they'd give you a bigger vote/tip, etc, if it had a positive impact. Other than that I don't see how a bot could distinguish what you're talking about.