If they were to create their own dedicated pool, where would the steem for the rewards come from? I think having the choice to enable this is a good idea, that way those who like bots can continue to have them upvote their posts, and those who don't can exclude them (Even though it is certainly possible to program a bot that gets through CAPTCHA). I don't see why a separate rewards pool is necessary (I don't think it is possible to make another rewards pool Steem can't just appear out of nowhere), maybe a separate category like the promote category. Anyway, I think having it so it can be turned on or off varying on the author is a good idea, so thanks for sharing that idea!