Have you evaluated durability with just the BAM case, and no key clamps?This is not an experiment in any way, but from my personal experience I purchased clamps after an overhaul was mailed to me and most of the keys leaked. I had sent it back as well as purchased clamps for the return trip and there were no issues. The few times I stopped using clamps I soon ran into issues with leaks.
Basically now I pull a swab through my sax after playing as well as clamps every time the instrument goes in the case religiously. I also play my sax around 20-30 hours per week with so many lessons and transport it in my car around 18-20 times per week for these lessons. With all of this playing and transporting, I only get my sax checked up once every six months or so and there are very few issues.
If someone is doing it wrong, there will be problems. But if they do it meticulously, I think there will be huge benefits.
On the flip side, key leaves are super easy to use and follow the opposite belief system. (Keys open). That works pretty well for making keys not stick and taking much less storage effort.
So to conclude, my sax has been through a lot, even an extremely hard hit, but in a Bam case and clamped keys it survives just fine.
And clamping puts ever deeper impressions in the pads. That equates to ever more compressed felt just where its resilience is needed, to cope with the issues of flexing metal and compressing linkage material where keys are linked.Clamps put permanent compression on the linkage materials, presumably compressing them, hence putting linkages out of adjustment.
(Note that none of the permanently closed keys have critical linkages associated with them.)