My only recent experience of at-the-gate-change is big jet to commuter jet change of plane, where they told me I could hand my mandolin in a gig bag over to the cargo guy or stay on the ground at the Raleigh airport. I did so with my heart in my throat. I bought a heavy duty case for it the next day in seattle, and have used it for flying ever since, and of course had that happen only once ever since. Still worth it for the relative peace of mind. I still remember seeing a friend's old Gibson mandocello case-in-a-padded-outer case dented by United. The mandocello was fine, but it was painfully instructive about how poor the protection from indifference or just bad luck is on an airplane.