This isn't viable because the systems these companies use to get the kids gambling is not obvious, even to a watchful adult. This is by design. Companies are also not obligated to give any information parents can use to identify this. Lastly, a lot of these games are free to get into, so the parents have no reason to know/ find out their kid is playing fortnite for example.

Again, these aren't circumstance, they are deliberate design choices to skirt the law and prevent potential action to stop it early.