Getting back to the thread (though I love the piccie Gonzo) ... if memory serves, our yellow plot (circle or shield depending on whether the plot is SR+SSR or SSR only) changes colour to red and starts flashing, and a tiny red 'E' appears to the upper right of the plot and remains there until the plot history decays to nothing.
It also sets off an alarm on certain of our consoles.
This is an AD system, though it is also used to provide the full range of ATC services. It has come on line in the last 12 months.
BA