If the mining are done at Google Cloud Storage, initiated by a google search bot, can't Google then identify and handle such abuse? I assume Google already scans for multiple types of abuse, such as sites that spread malware.
Google shouldn't really have to do this. Replace GoogleBot with BingBot or GCE with AWS and you still have the same problem. A website operator should be working to make sure search crawlers don't consume too many resources given that the bots follow rules.
Otherwise you'd have a team at every cloud provider trying to figure out how to manage bots.
Now you're suggesting that Google basically devotes a team to detecting "crawler-free-quota abuse", when the real solution needs to handles crawlers from many different sources that aren't all Google.
Otherwise you'd have a team at every cloud provider trying to figure out how to manage bots.