When I first installed VLC, I put it and its documentation in a new subfolder, /Applications/VLC/. (I do the same thing with other apps too, just to have a place to put the readmes etc.) That's never created any problems for me until today, when I tried to check for updates and got this error message:
"VLC can’t be updated when it’s running from a read-only volume like a disk image or an optical drive. Move VLC to your Applications folder, relaunch it from there, and try again."
So I did move VLC to /Applications/, and then the update check worked fine. But it seems silly that this is a problem for VLC, and the error message is quite alarming until you figure out why you're seeing it.
I did a quick search of this forum and of http://trac.videolan.org/, and I didn't find any references to this issue. Did I miss anything? If not, I'll file a bug report.
VLC 2.2.4 on macOS 10.12.4