[korlja]

Leaving your computer unlocked usually also breaks policy (except if the policy is very much useless). The non-embarassing way would be to report the user leaving the computer unlocked, leading to disciplinary action and eventual dismissal. I think something slightly embarassing is the kinder option here.

[Spare_account]

>Leaving your computer unlocked usually also breaks policy (except if the policy is very much useless).

Agreed. But at this point, only one person has breached policy and it's a forgetfulness/oversight kind of breach.

If someone actively takes control of the machine to send an email, that's a much more serious offence.