Perhaps they can talk it outside of school like with their parents on someone older than them? At least for me that is the case,
Some parents are just busy working and they forget to talk about important matters on their children so I don't see this as a bad idea. Kids can in fact get more motivated to listen if they see that they aren't alone but they have their classmates which are also listening on the same thing but I can see one disadvantage here and that is kids who aren't yet exposed in gambling, will get curious to know if what is it and they will try it. What if they themselves get addicted in the process?
although I have seen my father gamble, but I didn't follow him when I was a little. But they gave me lessons about gambling that I can't go play and understand the bad effects. So the education for me started at my own home and not in school. It's that when I grow up, have a decent job and that I was influence by one office mate to go to casinos, but I old enough that time.
I like the attitude you are showing there and also your father because I think some fathers will let their kids follow their path especially if their kids find out that they are into gambling and they confront them. You have waited to grow older and have your own source of living before you engage yourself in gambling. I won't worry with you now because for sure you still have a self discipline and won't become an addict later on.