corwinsl: Thanks, good explanation. I do know what an op upgrade is...was just being facetious, as I have never ever received one after taking hundreds of flights, whereas others seemed to have enjoyed a number of them. I do think that they may be more prevalent on certain routes (and maybe due to fare paid?), ones that obviously I am not flying. For sure, no miles or upgrade certs should be pulled if such an upgrade is offered, as such an upgrade also benefits UA.