It wouldn't have to go that deep. If we made not following robots.txt illegal in certain jurisdictions, and blocked all IP addresses not from those jurisdictions, then there would presumably have to be an entity in those jurisdictions, such as a VPN provider, an illegal botnet, or a legal botnet, and you pursue legal action with those.

The VPNs and legal botnets would be heavily incentivized to not allow this to happen (and presumably already are doing traffic analysis), and illegal botnets should be shutdown anyway (some grace in the law about being unaware of it happening should of course be afforded, but once you are aware it is your responsibility to prevent your machine from committing crimes).