When you select this option it will generate an email that is pre-filled with a bunch of debug data from your prior two sessions. If you are offline (ie, in the air), the email will simply sit in your outbox until the next time your tablet is connected to the internet.
Also, you don't need to write an explanation on that email, you can do that later at your convenience. Send us an explanation via email, or post on the forum like this, and we'll review your logs to try and find out what caused the problem.
Thanks!
Walter