If you have AT&T and an iphone, download the app "mark the spot" (not sure if there is an android app). Use the app to identify where you lost data, voice, dropped calls, etc. I use it all the time and have had two cell towers repaired on my commute to work that would have been offline for who knows how long.

I doubt they are intentionally blocking signal. Imagine the lawsuit if a 911 call couldn't get through because of an intentional act? More than likely, there is so much interferance and signal degradation from being indoors that the voice/data can't transmit. The last thing any casino wants you to do is go outside!