People come to the gate all the time with the Cast ID and main-gate pass of a CM they're related to, however, if the CM is not present, the ID and Main Gate must be confiscated. Unless your name is printed on the pass and you have your own photo ID, you are not entitled to benefits from it. The only benefits expressly connected to the Main Gate/Silver Pass are park admission and parking.
Having someone else's ID or knowing their SSN does not prove anything, and I would hope that our CMs are not encouraging that type of thing (what's to say I didn't just find your wallet with ID, SS card, etc inside?)
Now, If I were working in a shop and a spouse came in with a silver pass with their name on it, and they had their own driver's license proving that the pass belonged to them, and if it were possible, I might occasionally make the exception and grant a spouse the discount. However, IDs are typically scanned or swiped to record use and validity, so I don't think that's a very likely scenario, and if it were, it would be an exception.
Golf, they might be able to no sweat, and if so that's VERY NICE of them, but they aren't required to do it.