As I understand the Texas penal code, a legal knife in Texas is legal on a school campus. It looks like your school rules for students can be interpreted to mean that they really do not want students carrying knives around with them, but "house rules" are NOT THE SAME AS STATE LAW. So, a legal knife being carried on campus cannot result in a prosecution for the knife itself. BUT, not following HOUSE RULES can result in expulsion from the premises, and if the expulsion is resisted, i.e., you want to make a stand and argue for your "rights," then it is possible to be arrested for criminal trespassing. Not likely, but possible. This is not legal advice; I wear a badge, but I am not a lawyer. The best bet is to be discreet, carry a relatively harmless-looking knife, and be very meek, mild, and apologetic if confronted by school authorities. And, be aware that there is very much ignorance of the law on the part of security and police personnel. One more thing: it would be best not to push the limits on what is legal, by staying away from anything that could be considered a dirk or dagger, which means mean-looking knives are not the best in non-permissive environments.