But no one is advocating that those people be allowed to "roam the halls". We are advocating that specific people be allowed to go to a specific room to consummate a transaction originated by the occupant of that room. If the delivery person then took that opportunity to then paper the hall with flyers, then I can absolutely see the objection. But that is not what they were invited for -so it is clearly outside of permissible use.

Look at it like this: Driver shows up at front desk and says "I have a delivery for Mr Jones, in room 1327." Clerk looks up room 1327 and validates that Mr Jones is indeed the occupant of that room. Clerk phones Mr Jones and says "I have a delivery person from Mama's Pizzaria here, would you like for me to send them up?" Mr Jones says "Yes, thank you".

In that model, the bad guy would have to know that there was a Mr Jones at the hotel, know his room number, know that he ordered from Mama's, and beat the delivery driver to the hotel. That pretty much only happens in the movies.

Or, in my experience, the bad guy can just dress in business casual, walk into the lobby and straight to the elevators like he belongs there, and do whatever he wants - without the front desk clerks even noticing him.