catch on, catch up

There's an email running around a few sites...a particularly long and cringey kind of email...from a guy who went out with a lady and said lady ignored him and he wrote off huge cringey email. And as amusing and sad as the email was to read, I'm sure there are two sides to this story and geez, how awful (for the sender and the receiver) to 'leak' that email around the internet.

But, if one incorporates the people that they meet (when they're walking down the street) into her blog posts or fiction (or emo-centric poetry), isn't that similar? I would never (ok, almost never) use real names, but I have used real events (frequently), more as a reaction, more of a "I can't believe that happened!" and less of a "look at the freak and what dumb stuff he did!" Is that fair to the other person(s)? Should a writer, upon first meeting someone, warn that anything the person may do or say might eventually end up in a lyric or a short story? Or is that just simply poetic license, taking liberties with stuff that happens and the people around us (and hopefully changing names to protect the innocent)? Or have I just been watching too many reruns of Dragnet?