Mail Goggles from gmail

I was reading this post from Gmail blog about a new feature called Mail Goggles.

When you enable Mail Goggles, it will check that you're really sure you want to send that late night Friday email. And what better way to check than by making you solve a few simple math problems after you click send to verify you're in the right state of mind?

and

By default, Mail Goggles is only active late night on the weekend as that is the time you're most likely to need it. Once enabled, you can adjust when it's active in the General settings.

I can think of a few websites that could use this. I can recall some posts at the old PGL website that the author regretted later. Of course I've seen some posters who probably couldn't do math even when they were sober so maybe it would filter out too many posts. Heck I probably couldn't do simple math problems on a terrible headache day.