
Since no one is touching this on UPGRD, I'm coming out of the dark for a moment to fill you in on what you probably already knew.
In the past, most Delta (DL) people have moaned about the relative uselessness of SWUs, formerly known as PMUs. I always felt obligated to use them when they simply showed up - before we had a choice in getting them. For me, it always made sense to use them on a K fare to Hawaii, or when an I fare was more expensive than an M to Europe. ...
