Felli who's that you're applauding ? ?
I made this extension primarily for development/debugging purpose on my local install, and I know it can be great to troubleshoot user accounts without asking for their password (of course it's nicer to ask the user first anyway).
I don't think additional warnings or notifications make sense. If an admin wants to sneak into a user's account there are already multiple ways of doing so without the user noticing. This one is just quicker and easier to use.