Show notice that site Network Admin is viewing is disabled

[MadtownLems]

In Multisite, site admins can click "delete site" from their Tools menu, but this actually just sets it to disabled. If a Network Admin tries to view the site, they can still view it just fine. This can be pretty confusing/misleading. I think it would be an improvement if while a Network Admin is viewing a Disabled site, that a message is displayed along the lines of:

This site is currently Disabled. [re-enable link]

Where are you thinking the message would be displayed?

Well I was hoping some UX experts could help out there. I developed a plugin for our site admins here that lets them take their site "offline" temporarily, and when a Site Admin or Network Admin views it, it displays a 50% opacity overlaid yellow bar across the page near the top that says:

Your site is currently displaying an offline message to regular visitors. You can change those settings [here].

(but it's admittedly a bit intrusive).

I also considered throwing something in the Admin Bar, hopefully with a more attention grabbing background color.

In WordPress MU super admins could not access a archived, spammed, etc. site. We changed that to the current behavior intentionally.

As someone who has a few networks with multiple super admins, I can look at a site spammed by one of the other super admins and easily see why it was spammed.