There is a US postal office in Las Vegas that shares a parking lot with approximately twenty stores, including a bank, a Trader Joe's, a Big 5, and several other independent businesses. The USPO leases one of the smaller spaces just as the other businesses do. There is absolutely no indication from the street that there is a post office in this center. No signage whatsoever. If you didn't know it was there, you wouldn't even look for it.
According to the defendant's argument in Bonidy lots of people would be in violation of USPO policy in this shall-issue, open carry state.