Originally Posted by
stargold
Earlier, you said that collecting miles on one program and using the benefits from another "is a trick to try and evade the rules, which may or may not work. You are only entitled to use one frequent flyer membership per flight."
I eagerly await your further evidence of the airlines' published policies regarding this issue. Particularly since you mention that it is "a trick to try and evade the rules", which implies there are such rules that are being broken.
I really wanted to ignore this impetuousness. But then I used google, and started at the top. And sure enough, Alaska Airlines rule? "When using MVP or MVP Gold benefits, including First Class Upgrades, mileage may not be accrued in any other airlines' frequent flier program."
I don't have the time or inclination to check every airline known to man, but I would hope this satisfies you.