These hotels are OK to bring your GF you register at check in (I don't do hookers, so cannot say 100% it's the same)
Most of the hotels I describe from the observations, even though I have stayed at all of them
Hilton - at check in ONLY / not required to be present / will have to submit cedula later
Jaragua - at check in ONLY / not required to be present / will have to submit cedula later
Melia - at check in ONLY, presence required, and security is very nasty to Dom girls
Mercure - check in and later
Hodelpa - check in and later
Marriot - check in and later
Napolitano - check in and later
Palacio - check in and later
Embajador - at check in ONLY / not required to be present / will have to submit cedula later
Clarion - check in MOSTLY / not required to be present / will have to submit cedula later (check in later - if really GF, no probs if she does not look like a hooker)
Sofitel Frances - check in ONLY, required presence