Actually.. most hotels that are 3 star or above generally do not care as long as undue attention is not brought to their location.
If you are worried about security and safety-- avoid the lower end hotels.. The Motel 6, Super 8, etc....
When I have a gent visit me at a hotel (I tour frequently)... I always given them specific instructions to the elevator as well as my room so that they can walk in like they belong and know where they are going. I also always ask gents to NOT bring flowers, as it does attract more attention. Other than that.. if you are staying with safe, reputable ladies-- you shouldn't have any issues whether she is in an apartment or a hotel. Apartment neighbors can report too much activity just as easily as a hotel.