Would it be possible to have Illustrator warn on saving that you have items hidden and if you select all and then try to move elements could it warn that you have items locked. I know this seems random but the way that we use files this would be a great feature to prevent errors from occurring. Many times as you are working you may hide something and then forget to show it and that item will not longer be part of the art. Also, you may lock something and then not realize and you move the entire art and this doesn't come along with it.