Just what can be done to ensure limited exposure of this kind?
instead of limiting exposure, why not educate them about it? I mean, educating them about gambling and the risks and what it can do to people, is one of the best ways to let them know that gambling can be dangerous and there can be grave consequences when it is abused. I have been mentioning it a lot on this forum whenever a topic like this pops up that "gambling awareness" should be added as a curriculum in schools or at least a subject about addiction in general.
With those action made it will just rise up the curiosity of teenagers especially if there's no further explanation on why they had been restricted to participate on such activities. To many means to access online casino now and for sure that they would see a lot of gambling ads. So what I usually do especially on free time and they are around me I watch gambling addiction documentary and make sure to increase the volume of the video I'm watching so that they can hear those unfortunate stories and realize that excessive gambling is wrong.
I believe this little efforts will result something and so far didn't see my child participating on any gambling activities yet. Proper guidance and education is important especially know that online gambling becoming famous to people and lots of hype to earn money easily is been promoted by those social media influencers.