My understanding was that there was no detector after registering for your room, but there was one thru the front door.
I have absolutely no first hand info.
Paddock was married and was in the process of getting a divorce but not from Danley, but another woman. (PER MSNBC, sorry that is all I have for national news)
I do have first hand knowledge, having helped plan two humongous Vegas events this year (35,000+ people). There are no metal detectors at any hotel lobby entrance or guest room areas that I know of in any hotel.
Many hotels let monthly tenants and guests once they have a garage card go direct to the residential floors from the garage.