Normdale, welcome!
Yes. I personally have brought back gals to Los Suenos. There is only the security gaurd at gatehouse and they ask for your room and name. I just roll down the window and beat them to it and gate opens...
Two signature moves I will share with everybody: I always list a Ticas name on any hotel I check into and I always bring a size 8 pair of Vans for chicas to wear.
This also helps insure I bring a spinner back, cuz if her feet are bigger than 9 (scrunching into shoes), hell I shouldn't be bringing a beast like that back anyway!!!!!
When you have a chicas name on reservation, it's easy and very normal to pretend it's your girlfriend. It has never failed yet. One note is I am able to speak passable Spanish and I keep everything low key around nice restaurants and hotels....hotels like the Marriott, imho, are more concerned about the guests getting pissed off....you get her heals off and put your arm around her like a gf and just stroll in like a normal couple.
Go for the full on name and don't be shy: Maria Tatiana Desoto Salazar.
Again, once you get past entrance gate, no problem....ditch the heals and have her wear shoes and it tones everything down a level for the Marriott.
Cheers