As far as I am concerned that's the problem with the Zone concept. Folks looking to double team, in some cases you just don't get them and cant allow that to brain lock your line. Uncovered kids need to realize that if the hat goes away from them they have to go next level. Covered kids need to realize that they aren't always going to get help. Is zone beneficial? You betcha! Kids need to know how to block individually and then teach them to work with zone concepts. Pull and Replace is hard to accomplish without a ton, and I mean a ton of reps.
Zone blocking DOESN'T brain block kids any more than some of these GOOD GOD,GOD,TKO, and whatever other "youth friendly" schemes that are out there. In the youth game, all those blocking schemes that I mentioned above are only as good as the fundamentally UNSOUND defenses that are out there. For example, if I teach my O-Linemen how to reach block, and the opposing DCs DON'T teach their kids how to defeat a reach block, I have the advantage. If I teach my O-Linemen the proper way to combo block, and the opposing DCs don't teach their D-Linemen how to defeat a DT, I have the advantage. In the youth game, it's about what YOU teach, just as much as what your opponents DON'T teach...