He needs to tell every.fare. that he cannot transport alcohol as soon as they get into his cab.

Had he not heard the clink of the glasses, he still would have been guilty of transporting alcohol.

Absolutely nothing wrong with his beliefs; I kinda dig him sticking to his them. It would have just been easier for everyone had it be explicitly stated somewhere/somehow.

He's also lucky you're not the kind to elevate an issue. I imagine not everyone would be as understanding.