I've gotten the infamous SSSSSS before, but every time I was able to identify what it was -- usually traveling on a last-minute one-way reservation with an airline on which I am not a regular -- that triggered it. But this morning, I was SSSSSelected on a BOS-LGA US shuttle flight. I am silver preferred on US, booked the flight as part of a round-trip with my corporate travel agent as I always do, and had upgraded to F as I always do (or as I always try to do). I cannot think of anything out of the ordinary about my travel this morning. Maybe some SSSSSs truly are random. Any thoughts?