CO would not give me a COMP until I took my UA statement to a City ticket office showing how many miles I had flown. They base the comp on miles flown with the other carrier, not status with the other carrier.
So, I don't know how valid it would be to get comped on another carrier, then try to take that to CO for a comp. You're not going to have any "miles flown" on that carrier where you were comped.

[This message has been edited by mlbUMP (edited 02-08-2003).]