Yeah,performance overhead aside, in Windows it reads and writes fine because of that. Anything thqt changes in Windows however will write the uid of that file as the windows SID I believe, either way I was using regularly the chown -Rf commands to reclaim files back in Linux.

It's mostly a problem with how steam handles updates downloading to temp folders, etc... It's the sharing of steam libraries that this happens to most often if you're back and forth between os's