I went through inspection last night and they failed me for the tank. Guy said there's a leak between the tank and the charcoal canister. This was the first time they've even opened my hood. Talking to Andy this am, he said he doesn't think the system is intended to hold pressure, just for vapor recovery.
CJ guys, did they ever go under your hood? Did they pressurize your tank or just test the cap? If they haven't done it to mine in the last 30 years, I'm going to see if I can find a supervisor at DMV who might know more about it.