My Dad was booked today on the 2:50pm from EWR to TPA on a Q ticket originating in LHR. He is UK gold (free PC club membership I might add) but did not receive an upgrade prior to today. He went to the airport early to standby for the earlier 11:30am, which looked full. He also checked in for the 2:50pm. He asked for the upgrade (we had checked and it was wide open) and he was told the following "those seats are reserved for revenue passengers and you are flying on a very low fare code". As it happens he made the 11:30am so it became a mute point but it sounds to me like she based his "upgradeableness" partly on his Q ticket.