Commercial gambling ads will be available only in the countries who supported gambling to grow and probably your government let this happen because they admitted gambling as industry and can be good source tax for them but besides all of it i think they will also thinking the risk behind it especially i read your post that there was casinos near to high school locations and it's very risky to childrens at there will attempts to gambling because casinos is too easy to be access
As far as the risk of casino is concerned to the school going children, it does not matter if the casino is built near the school or not. As gambling is available online, anyone can easily access it at any time. By using bitcoins, one even does not need credit card to play gambling which makes if further more easier.
I guess for countries that legalize gambling they will not make a proposition when gambling place is near their school. And maybe not a place that must be really shunned, because if a child has an interest in gambling, they will gamble in their own way. Online gambling is an idea to make it easy for every gambler, they are free to gamble in a place they like, and also a place that is most liked by every gambler who prohibits gambling.