There is a valid reason for a CSH. For example: the other day I was in the mall with my female companion and we ran into one of my friend's girlfriends. They hugged and then we began to exchange pleasantries, but what am I to do? If I don't hug her, it looks like I snubbed her, but at the same time, I don't know her that well, so she might be someone who isn't big on hugging her associates. Obvious time for the CSH; properly cordial yet not offensive in case someone is touchy.