Don't we already do this with services like Let's Encrypt, which is arguably more sensitive? If you had the codebase you could fake it, but it would still provide some amount of protection against abuse.
replyWith Let's Encrypt, all the verification is done on their side with them controlling the connection between themselves and whatever they're trying to verify.
replyIn this case, you can put whatever you want between the harness you're running (or modify the harness itself), and essentially "lie" to the model. Any verification technique would be fairly trivial to bypass, while you continue to run the harness locally.
Yeah, for web apps, you can trick models by simply proxying it and pointing the models to that localhost. They then think they're not working on a live target.
replyHave personally tested this with Opus and Sol and it works.
Classifiers are tricky though. Here's where open weights will win.