If you run a website, it seems trivial to forward the attestation to someone else by putting the same code up on your website, and getting their device banned from google instead of your own.
The camera isn't the part doing that verification. The google service serving that "reCAPTCHA" is what's doing that validation. Unless you're using a custom browser that is reporting a different domain to google than the one requesting the reCAPTCHA, google's service will know which domain is which.
It would be generated by some other website like Amazon. Because I own, say, Meta, I copy these Amazon-generated codes over to Meta, make people scan them on their phones to sign into Meta and then pass the solution back to Amazon so my bots can sign into Amazon.
Realistically, what Google will do in such a scenario is collect data about the illicit service, enumerate the devices the farm uses and what other activities the devices participate in. What you suggested has far less control over the devices that generate the attestations and it will show.
Also, if the implementation is competently done the phone will show the website for which you scanned the QR code. A user would be able to see whether or not that matches the site where they observed the QR code and proceed accordingly. In time Google will probably integrate it into the Chrome browser where a proxied QR code cannot even be shown.