Originally Posted by jasonvr
I just tried one and it got rejected with a message about the cert only being good for roundtrips.
-Edit: My mistake, I tried with a %off cert, not a $ off cert as WindFlyer was asking about. I don't have any $ off certs available to test.
I recently tried using an entertainment book e-cert ($ off), and united.com gave me the same error message whenever I tried to create a multicity booking. When I called United phone support, they said my routing (BOS-SFO-PDX-SEA-PDX-SFO-BOS) was "not a roundtrip" because the stops weren't in hub cities and therefore did not qualify for a discount.