Once in a while it happens.  You've got to forget about the model release it could compromise the shot.

It happened the day I was shopping with my wife for a swimsuit at a lingerie shop in the mall.  I was just a little bit out of my comfort zone being in a shop surrounded with skimpy under ware so I was quickly glancing around the store for the swimsuit section.  As I was walking around the many racks of bras and panties, tucked away behind several displays, I was struck by this couple.  I could tell they were having some kind of disagreement.  He was looking calm and reserved when I arrived on the scene but the body language of his partner showed that even though they were once close just moments before she now was pretending not to know him at all.  I could easily relate to his situation ... I've been there too.