just to update-
it did not happen when i took 174 to bos on march, 16th. i even walked very slowly and made direct eye contact w/the tsa person at the end of the "bull pen" to see what would happen-go figure.....
so in summary:
march 3: 24-jfk-no
march 10: 24 jfk-yes
march 16: 174-bos-no