It is a bit ridiculous. If you really believe that your “secret sauce” is the prompt you are using then you don’t have much of a business. So I would agree - it is partly just corporate paranoia. It would be nice if companies were just open with their prompts.
I say partly paranoia because if they didn’t make some attempt everyone would be jumping up and about how they managed to get it to say something “bad”. There’s a reason why we can’t have nice things…