Medieval flashers

One of the things on my list to do before surgery in Septermber (and really, I need to get this done before Pennsic) is make a cloak.  So I was duitifully looking up pictures of ladies matles last night in between eylets, and came across the following page from the Manesse Codex:

If you look closely, you can totally see through the men's tunics. Good thing he seems to have all his proper under things on.

I wonder if they were being presented in a state of semi-undress, or if they really did wear semi-sheer tunics?  Either way, I'm not letting my husband see this one, he doesn't need to get any more strange ideas for hot events.