Cal Poly's Perspective
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.
Campus Administrative Policy 171.2 (Smoking Ban)
On campus, in order to protect the rights of the nonsmoking community to breathe smoke-free air on campus, smoking is prohibited in all campus buildings, leased space, and all state-owned passenger vehicles. The only exceptions to this prohibition are private residences on campus. Resident students should refer to the housing license and the University Housing Resident Handbook for specific policies.