Plus, though we FOs technically don't have this privilege on paper, last year in BOS I arrived Mon morning and the security line was hundreds deep and moving at a snail's pace. Screw that... I flashed my Silver card at Sky Priority and instead of watching everyone in the airport do the TSA dance, I was enjoying breakfast.
Sounds like you got lucky - the bouncers in the SkyPriority line at BOS are usually pretty good about keeping out the lowly FOs. I wish the GAs were half as adept at enforcing zone boarding as the security folks are at enforcing the SP line.