I've seen and heard this before, but in all occassions it was down to user error. To send an email in online mode, you can do this by; a) clicking on 'Send' button b) clicking on 'File' > 'Send now' '''c)''' hold down 'Ctrl' key and press 'Enter/Return' key. In those cases this is what happened. The person was typing /composing an email and on occasion used the 'Enter/Return' key to move to another line. However, they had unknowingly also pressed the 'Ctrl' key at the same time, which resulted in the email being sent. As this type of error is down to the user learning to modify keyboard use, for example: often resting the left hand near the left lower corner of keyboard, (but their are 2 locations of the 'Ctrl' key), I suggested they created their emails in 'Offline' mode whilst learning to stop the habit they had inadvertantly got into performing. So, even if they still managed to select 'Ctrl' + 'Shift' + 'Return' (still possible as those three keys may be in alignment on the right side of keyboard) the email would end up in the 'Outbox' located under 'Local Folders' account and not be sent, so allowing the person to check the Outbox before returning to 'online' mode and then using 'Send unsent messages'.