SpiraMirabilis
Possible Subversive
I'm pretty sure that regardless of PSA's policies, federal law states that airlines shall allow them to stow them in the bins:
(1) Small instruments as carry-on baggage.--An air carrier
providing air transportation shall permit a passenger to carry a
violin, guitar, or other musical instrument in the aircraft cabin,
without charging the passenger a fee in addition to any standard
fee that carrier may require for comparable carry-on baggage, if--
``(A) the instrument can be stowed safely in a suitable
baggage compartment in the aircraft cabin or under a passenger
seat, in accordance with the requirements for carriage of
carry-on baggage or cargo established by the Administrator; and
``(B) there is space for such stowage at the time the
passenger boards the aircraft.