I do agree it's tough - in the airline business there is a stream of folks who ask for exceptions and have excuses. It is one of the facts of the business. Customer training and an appreciation for knowing that it makes business sense to go the extra mile (repeat high-yield customers) and try to help and check out if the gent was a member might have resulted in a simple scenario: "Mr x, I called the WP desk and they tell me you are not an Elite member - would you like to talk to them directly" or "Mr x, the WP desk says you are indeed a WC member. In the future, if you can bring your card it is very helpful because when it's busy, it is sometimes hard to make a phone call."

I don't think expecting the agent to do either of the above is unreasonable.