I called an admin in an offshore office on his mobile, and asked him to reboot a hung email server. He came back to the phone telling me it was done, but I was still moving the mouse around on the hung remote session. When pressed to confirm details, I couldn't recognise the server name he gave me. It all became clear when we figured out he'd changed companies, kept his mobile number, and had just rebooted his new employer's mail server. Oops...