Ever heard of those stealth radar devices used to hide your car from police radar?
Someone's been watching Knightrider a bit too much. Radar detectors alert you when there's a police radar nearby but that's hardly the same thing and kinda screws with your metaphor.
OK, not the greatest analogy, but radar stealth exists. It's called a radar jammer http://www.radarbusters.com/support/jammers/Default.asp
, which, on a side note, don't really work.
And what does the stealth do on the 360? It hides the fact the drive is modified from the 360 itself and, in turn, Microsoft.