I bought and used key clamps on my alto for awhile, until I spoke to my repair man about them. However, after hearing, "Keyclamps? Repairmen love them - they provide plenty of work.", I stopped using mine. When I quizzed my repairman about clamps, he spoke about damage to pad seats from excessive clamp pressure. Perhaps, as Saxman has said, a lighter pressure would be ok. I might try using them again with a lighter pressure setting. On another note, I too love the Protec propak case for my alto.

Your horn will fall out of adjustment under the stresses of playing far more than a bumpy bus ride, in my opinion. What's most important is make sure your horn fits tightly in the case. If you can feel your horn thunk around in the case when you shake it, then you need to either get a better fitting case or add some bubble wrap and such to help secure it. Just be sure that anything you do doesn't stress the rods or posts laterally. There are varied opinions on the use of key clamps. Their benefits, I feel, can be justified to some extent. The trick is to use clamps that work lightly. Hard pressing clamps would likely alter the adjustment of the horn. It would settle in after some amount of time, though. Many horns have survived without the use of key clamps. Few horns have survived without a proper fitting hard-shell case. Does your bari have double arms on the bell keys?

My bari is a 1955 Mark VI (believe it or not), which is the reason I was concerned about the bus ride. I have a protec case.

Here is a link to a page with the case I have. Its the protech pro pack contoured bari case. www.music123.com/Baritone-Sax-Cases-d1957.music