Yes that's apparently, the main theme for this latest addition to the Gmail Labs. It will be useful to those who send messages without thinking (includes me) and then later regret it. It can also be used in situations when you are drunk and are accidentally transferring all the balance in your bank account to your neighbor's.

Gmail labs is known for its addictive tweaks. I personally like to use my Gmail with mouse gestures and custom label shortcuts. But today's addition seems to be a bit odd and out of place. In simple words, it will ask you to solve some math related questions before sending your email. This would actually be helpful if you are subconscious and/or not in your senses (but who would write an email in this kind of situation?).

Nevertheless, it can be tweaked further to enable at specific times and days of the week. By default its enabled for the late hours on weekends, when the probability of "drunk emails" is high. Most of us would just pass by this new feature because solving more math problems would be the last thing you would want to do when sending in your calculus assignment late night. But for those of us who have suffered break-ups due to such situations, this addon might prove useful.