I must disagree.
Some will tell you that federal law - 18 USC 922(q) disallows open carry in school zones. And the statute does say that.
But, since Congress amended 18 USC 922(q) there has been two courts that I know of that has upheld Congresses changes See United States v. Dorsey, 418 F.3d 1038 (9th Cir. 2005); United States v. Danks, 221 F.3d 1037 (8th Cir. 1999). Both are contrary to Lopez.
Hodel v. Virginia Surface Mining & Reclamation Assn., Inc., 452 U.S. 264 (1981), United States v. Lopez, 514 U. S. 549 (1995) and Gonzales v. Raich, 545 U.S. 1 (2005) all made it clear that under the Commerce Clause Congress is required to show a tangible link to commerce, not a mere conceivable rational relation. “imply because Congress may conclude that a particular activity substantially affects interstate commerce does not necessarily make it so.” See Lopez, supra, at 557, n. 2 (quoting Hodel, supra, at 311 (Rehnquist, J., concurring in judgment).
The Lopez Court made it clear that the Commerce Clause would not carry the day when it comes to carrying a gun in a school zone.
The possession of a gun in a local school zone is in no sense an economic activity that might, through repetition elsewhere, substantially affect any sort of interstate commerce. Respondent was a local student at a local school; there is no indication that he had recently moved in interstate commerce, and there is no requirement that his possession of the firearm have any concrete tie to interstate commerce.
I suggest you read Lopez yourself.