Hi Bradley,
EDV will be sent regardless to the extension, but one of the properties is is_suspect. You can do with that what you will, either terminate the session, perform step up, or move on. There are of course several other fields passed in with that object for you to action on.
In terms of adding EDV in front of existing extensions, it's possible to configure an SSO to do this in newer version of UUX, but it's just the system's built in step up, not necessarily a custom built thing provided by you.
Brian