CMC has one of the most relaxed substance policies of any school in the 5Cs. Literally, no one gets in trouble for drinking—even if they are underage. Students party in their dorms and outside, in plain sight of campus security, without any worries. There are only two basic policies for drinking at CMC—"the red cup" policy, and know your limits. "Red cup" policy states that anyone can drink a beverage in a red cup, and authority figures won't ask what's in the cup. That said, after several hospitalizations and much talk of redoing the relaxed alcohol policy, the unwritten policy is merely know your limits—if you don't pass out/need your stomach pumped, it's fine. Alcohol is readily available at dorm parties and bigger parties, and it's usually paid for by student government. Most students are accustomed to drinking for free.
The marijuana policy is tricky at CMC—as it is all over California. Some students even have their own medical marijuana cards. Smoking is done inside and outside of dorms, in a relatively discreet fashion. Marijuana is as hard a drug as most students get, and anyone who does anything else does't talk about it. CMCers like to let loose and unwind with various substances, and, for the most part, the administration is OK with it.