Is the domain and subdomain page consider as 1 site? Will I violate the adsense policy if my sub-domain page has Gambling or casino-related content?
You should ask them. You might also be interested in this post at Jensense: http://www.jensense.com/2008/06/24/adsense-going-through-major-compliancy-checking/
I think when no one reported your site you will not receive a warning. I'm just wondering why a friend of mine don't receive that warning.