The University's Perspective
Use, possession, manufacture or distribution of illegal drugs or drug-related paraphernalia, (except as expressly permitted by law and University regulations) or the misuse of legal pharmaceutical drugs is against the Student Code of Conduct.
Marijuana is against Campus Policy as of The California Code of Regulations Title 5.2 §41301(b)(9) and the Cal Poly University Housing contract both prohibit the possession of and use of illegal drugs or drug-related paraphernalia on campus, including marijuana.
This means that a medical marijuana card is not a defense for using or possessing marijuana on campus.
Valid medical marijuana cards are only used as a defense to a criminal charge.
Refer to Campus Administrative Policy 170
As of Campus Administrative Policy 171, the university is a Tobacco and Smoke-Free environment and it is prohibited to use these substances on campus
Refer to CSU Executive Order 1108