Reply #34: what law is this?

[iverglas]

This is a term in a commercial lease sort of thing, I believe.

Would it be unlawful to require that vendors at a wine exhibition at the fairgrounds, where wine producers display and sell their wares, that they require proof of the purchaser's age before making a sale? How about that an operator who leases the fairgrounds to hold a beer garden event require proof of age before serving a customer?

Assume that the law doesn't require proof of age when a sale is made, it just prohibits sales to the underaged.