Re: Hide extensions for known file types
No, as I understand it there is no attachment, rather there's an image attached and displayed in the email. The image is designed to look the same as a normal Gmail attachment link, with the attachment name shown to be one you'd legitimately receive from that contact. So you click on what you think is a Gmail button but which is actually just a link, and get sent to the dodgy page.
That said, I also think they should have binned the hide extensions default long long ago, and I'm amazed it's remained the default even on the latest versions Windows! In addition to the security issues, it's a support issue... I've seen so many people accidentally break their file associations and then not understand why they can't open certain docs. Un-hide extensions and you immediately see that no, it might have a PDF icon, but you're actually trying to open a docx file.