I have been Platinum for 2 years and fly out of PHX to ITO about 15 times a year. On one occasion I was upgraded to FC at the gate. In this case they needed my seat for a minor flying with her mother. I have been on the flight many times when they left with empty FC seats. I once asked for a comp. upgrade and they told me they never give upgrades without $ or points. That flight left with open FC seats.