mickey
Like you I have heard of this happening, but do not know anybody that it has happened to.
However as I get ready to leave for ZIM this Friday I do know that I AM worrying about it.

I would hate to get to Africa and not be able to use my rifles. I might be able to find some ammo for the 9,3x74R but would be pretty much out of luck on the 450 No2.
It is probably not as big a problem as we make it out to be.
The main advantage of a 375 H&H double rifle is for guys who are not confirmed rifle cranks, and would like to have a double they could use here in the states as well as Africa, and guys that do not want the big recoil of a 470, and even for guys thet do not reload and will be shooting factory ammo [that is "affordable"].