Well, none of that is really relevant here, since there’s not even a menu. Let alone BD-J. It’s possible that some players could glitch up if they don’t see the folder, but I haven’t seen it happen (for BD-Rs at least). With the constant updating of BD firmware, I’d be surprised if it’s an issue, but yeah, in theory it could only help compatibility by including an empty folder.
Yup! That’s exactly the issue, some players expect that folder to be present, empty or not.
I saw “PowerDVD” named as having this issue. Perhaps hardware players too.