That’s BS, I’ve done it many times, every once in a while, you get the douche that gives you that line. Try another store, or don’t tell them it’s a firearm.
From the ATF.gov site question#6
https://www.atf.gov/resource-center/docs/0501-firearms-top-10-qaspdf/download
Its the taking possession of the firearm that gets me. Wouldn't the hotel be taking possession?