I think it can, in a way. Create a witness approved list of bots that are blacklisted from contributing to user-rep in any way. Without the rep boost, there shouldn't that much fear that bidbot users will come back to retaliate when regular users flag their posts because of disagreement with the projected payout. Maybe add self-upvotes and related-account (proxy/recovery links) votes to the equation of don't count toward reputation votes.
Then do one huge blockchain level rollback of raw rep points that shouldn't have been counted so all those poor content bidbot using accounts drop back to the thirty something rep they would have had without the bots.
That is: fix the reputation part in the blockchain and the community might grow the balls to self-regulate more. Might take some time for people to grow their balls, but with some backing blog posts from a few top witnesses, after such a blochchain HF action, I think the current inflated rep caused flag-phobia could be put in remission.
This is a consensus rule, so it must be enforced by a hardfork. Which means we would have to do a hardfork every time we add somebody on that list. Not feasible.
Couldn't you just have witnesses (and/or the account owner) cryptographically consent to additions to the list after the use of the list is added in a single HF?
Consensus doesn't work like this. It's a more complex question that atomically accept / reject changes. Also, involving witnesses in this thing could lead to competition - some of them may consider some bot legits, other not. It's opening Pandora's box.
No, you would definetely need consensus on the idea that bot votes shouldn't count towards reputation and that account holders should at least be able to do some kind of irreversable discretionary drop humanness operation, and that self votes and related (proxy/recovery link) accounts shouldn't count to rep either. The pandora's box part I think, would be limited to agreement that an account that didn't discretionarily drop its humanness should be on the list nevertheless. I could imagine that if someone were to make a hybrid bid-bot that in fact includes some form of owner curation (Ok, if the #1 bid is crap and the #2 bid is not, I'll upvote #2 instead), there might be some strive.