So what do you do when you see.. ?

So what do you do when you see an ad posted on Craigslist and you read it and you find out that this is someone you know who has a boyfriend and is looking for somebody else in the missed connections site?  Do you tell that friend what you say and confront them?  Do you keep quiet?  Do you tell their boyfriend?  Do you look other way?

Why me?  Why did I have to be involved in this?  Just because I troll the internet so much, or because I am so smart that I can put two and two together and figure out that this is definitely four.