Having some time to kill and really curious after trying to book a similar offer before, I decided to do a little experiment here. The results were surprising to say the least.
First background - I only played at Cosmo one time and while I was hoping to give them a solid day of play, I ended up having horrible luck and played about 4 hours at .25 and .50 level and lost about $500 before I called it quits. I also had a horrible headache and decided not to play anymore.
Received an offer for two nights (assumed comp) and tried to book it previously and was quoted $129 per night plus taxes. I honestly don't know if they have resort fees so not sure if that hidden fee would have been tacked on later anyway. Of course I said no. At the same time I went to their website and didn't enter the offer code and was quoted the same rate of $129, so technically no difference.
Okay, today I looked up rooms and was quoted online without any offer code for a city room for June 14th - 17th (3 nights) for $160 each night. Okay, so then I enter my offer code and I am quoted $140 for the first two nights (savings of $40 off of regular price) but the third night I was quoted $200 a night. WTF??? The net is still $160 a night but since I put in for three nights it discounted $20 for the first two nights and charged me more for the third night.
I was literally being sarcastic on my previous comment, but it appears to be the case. I didn't call anyone and just did this online, but was surprised by the result, especially after losing $500 there back in March.
Oh well, Cosmo is too rich for my blood I guess. I would like to stay there once but will wait for a better (hopefully complimentary) offer before I do.