Yes, but is that happening? I think the answer is no. The mere ability to pass huge structures does not cause programmers to do that.

I believe the same would be true if the language allowed passing arrays. Programmers would not generally pass them around. There is no need for the language to protect us from this by failing to implement the ability to pass arrays.

I think I agree with that position. I seem to have gotten the impression that you were doing this and not seeing a performance impact, which has been wrong in my experience.