> The question is always whose surprise.

I think that the surprise of more data than expected is more desirable than the surprise of data loss. So in this case, it seems like the safe choice.

Agreed. I usually hate on Apple, and its terribly ancient utilities and gratuitous incompatibility with modern Linux utilities, motivated by hatred of the GPL license.

But in this case, I think what it's doing is… basically fine? "Tar should faithfully reproduce the semantics of the source filesystem" is a perfectly reasonable starting point.

Ideally there would be a documented way to turn off the Apple-specific metadata with Apple's own tar, though.