Help, I'm Stuck in London and Can't Get Home

This morning (east coast time) I got an unsolicited Facebook chat. The user was a former colleague (in fact, a former PCMag colleague), but not a Facebook friend nor were we ever all that close. We hadn't spoken in years.
He asked how I was, and then volunteered that he wasn't doing too well. "I'm stuck with my family in London,United Kingdom". I didn't to hear any more. This is an old scam, a social networking version of the Nigerian 419 where someone tricks you into transferring money or access to your bank account.

I disconnected and immediately went to find my friend's e-mail address and told him about it. Then I looked on Facebook, and found where you should go first if this ever happens to you.
Go to Facebook's "My friend's account is being used by someone claiming they are stuck in a far away location and need assistance" page. There you can tell Facebook what's going on. You have to fill out a short form. It's best if you retain the content of the chat, but it's not necessary.

I immediately got an automated confirmation from Facebook that they received my report. 6 minutes later I received a message that they "...have taken the appropriate action to secure this person's account." Furthermore:
In order to resolve this matter, please ask the account holder to view the Security section of Facebook's Help Center:
From here, they can take immediate steps to contact us and reestablish ownership of the account.

I think it's interesting, and not coincidental, that my friend lives on the west coast and I was on the east coast. That the message came morning east coast time made it reasonable that it came from London, but my friend was likely still asleep. I think it's also by design that he's not a Facebook friend, but we have many mutual friends. This made it likely that we knew each other, but were not in touch recently.
It also made it likely that I wasn't the person he would ask for help in such a situation. Common sense is usually your best defense against scams like this. Use it.