this is an obvious marketing strategy, but it looks like one that wasn't well thought out because through the adult content they display on the site a lot of potential customers wouldn't want to give it a try in the first place.
Who tells you? You do not know the way people are thinking. The only reason some people may not want to give it a try is to avoid scam. Let the site come up with a signature campaign on this forum and see how people will register on the site. What that is most important to gambling site than any other thing is reputation. If the gambling site has good reputation already, the will be traffic on the site.