No because the bots are running on compromised machines, so they'd just steal the real owner's micropayments. It'd also entrench search monopolies even harder,

No because the bots are running on compromised machines, so they'd just steal the real owner's micropayments. It'd also entrench search monopolies even harder, because everyone would exempt Google/Bing because they want to get indexed, but they wouldn't exempt other bots like the one you need for your new engine.