Putting in a stock GM stereo?

Now I heard somewhere that when replacing the stock stereo in late model GM cars you have to go to the dealership and they have to do something to make sure your replacement unit isn't stolen? Is this true? I do remember, when I borrowed my friends old stock CD head unit for my Cavalier years ago, and put it in my Cavy, it wouldn't work once the car was on? Does this happen to Camaros too?

Regardless of any theft deterrent system, the 2010 Camaro stock radio doesn't appear to be interchangable with any other car stereo on the planet, based solely on geometry.

It'd probably be one butt-ugly mounting kit....

I wish the new Camaro's radio would be one like in the Impala and Malibu, but not this. It looks like GM has already made their plans to go with a differently-designed, retro-designed stereo system.

And the reasoning behind that in late model GM cars is that the radio is used an an information center and to play the startup chimes and warning chimes through the speakers. You can put in an aftermarket radio, but you won't be able to hear the chimes.