Some time ago, a senior executive sent email to the All Employees distribution list at Microsoft announcing that a particular product was now available for dogfood. The message included a brief introduction to the product and instructions on how to install it. A few hours later, a second message appeared in reply to the announcement. The second message came from a different senior executive, and it went

I got your note and tried it out. Looks good so far.

Oopsie. The second senior executive intended to reply just to the first senior executive, but hit the Reply All button by mistake. This would normally have been caught by the You do not have permission to send mail to All Employees rule, but since the mistake was made by a senior executive, that rule did not apply, and the message went out to the entire company. People got a good chuckle out of this. At least he didn’t say anything embarrassing.

Bonus chatter: I’d have thought that these extra-large distribution lists would be marked Nobody can send to this distribution list, and then when somebody needed to send a message to the entire company, the email admins would create a one-day-only rule which allowed a specific individual to send one message.