This would be a nonstarter in the US. SCOTUS has ruled "minors are entitled to a significant measure of First Amendment protection." (Erznoznik v. City of Jacksonville, 422 U.S. 205 (1975)) This sort of blanket ban would collide with that.

I'm not sure if you've been following, but the current SCOTUS hasn't seemed to as concerned about upholding precedents as previous courts have.