It is not always possible to monitor the children using their mobile devices, because at your age they are a necessity, and with the number of social media platforms, we no longer know what they are really doing.
So the only thing we can do is educate them on this kind of thing that it is not good for children like them, so that at least they have an idea or familiarization that it will not do anything good if a minor does it.
It is very unlikely that we can monitor the activities of our children all day long, because we ourselves have our own activities to do. Some parents may be able to monitor their children's activities but they don't do it themselves, maybe they hire someone else to supervise them by paying attention to what their children do when they are not under parental supervision.
It is true that all parents can do is educate their children as best they can so that they do not make the wrong decisions in having something like seeking entertainment or pleasure for themselves. On the other hand, I myself do not dare to gamble in front of my children, however I will hide it because I think this is behavior that they should not see.