It does seem ridiculous because you could just as easily hide some of those guns with a tucked in shirt. Most likely if a school has that big of a problem they have metal detectors and clear backpacks.
Certain clothes would make it easier to identify that you had 10 hand guns and a shotgun in your pants, but I doubt everyone is carrying that.
Mainly I think it was done for shock value to support what was trying to be accomplished by the school board.
Ruger GP-100 4" .357 Magnum
Remington 870 Express Pump 20 ga.
Ducks Unlimited Single Shot 20 ga.
Sheridan Pellet Rifle .20 caliber w/ 4x scope