I think greed is the main reason why a lot of people eventually loses money when they are gambling, it's hard to change a greedy person when they are in dire search of money. Maybe attending seminars for greedy people will eventually help. 
It's correct mate, and definitely many gamblers loses money because of greed and no satisfaction of the winning amount they had. Most of the greedy person tend to lose a lot of money because in their mind they are aggressive to win the huge betting price, but everything will just turns out to frustrations behind all efforts. I think that seminars you are talking about if a person don't decide to change his/her perspective in life regarding that greediness aspects, anyways it's been discussed here; maybe this thread can help to those greedy people.