One tip that I will give you and it is always worked for me in the chain hotels like Radisson, Holiday Inn etc:
You book a double room (this is normally same price as single as you pay for the room and not number of people)
Then, if your'e lucky just bring the girl in, if the security or whatever try to cock block (or ask for bribe) ask to see the duty manager Immediately and threaten to write a serious complaint letter to the customer relations of the hotel chain as you paid for double room already and they refused to allow the 2nd person - this is serious accusation to the hotel and they can be in deep shit for that.
This always helps, although not so nice in front of the girl and they might still wishes to see her ID.
You book a double room (this is normally same price as single as you pay for the room and not number of people)
Then, if your'e lucky just bring the girl in, if the security or whatever try to cock block (or ask for bribe) ask to see the duty manager Immediately and threaten to write a serious complaint letter to the customer relations of the hotel chain as you paid for double room already and they refused to allow the 2nd person - this is serious accusation to the hotel and they can be in deep shit for that.
This always helps, although not so nice in front of the girl and they might still wishes to see her ID.