I got three similar messages over the weekend and since I have a desktop without a camera and don't go to the kind of sites mentioned, knew it was fake and glad this thread confirms it.
Before I switched to a desktop mail client when I used to use the web browser for outlook, there was an option if you right click on the message you could choose to view message source and see it in plain text and this would allow seeing the contents of the mail without opening the message and the message still shows as unread (unless you aren't careful where you click and then it changes to read), so if the sender somehow had it set up to detect that you read it, in this case, that wouldn't happen. When I can't tell for sure if it's suspicious, I'll go to the web browser version.