questions about component protection

Can I swap back and forth my tdi mk7 golf ECU with another compatible ecu with out having to do any programing? For example if I buy another ecu and have it programed to my golf by the dealer(if necessary), can I swap the ecu's back and forth as needed? I'd like the tune the crap out of one and still keep the stock Virgin one in case I need it. Is this possible or will some security feature prevent it?
I didn't notice the ECU part of the component protection constellation.

Also I know the cecm/bcm is component protected, but if I have a brand new one programed to my car by the dealer will I be able to put the old one back on in case something goes wrong with the coding of the new one? Or will the old/original one kick a component protection fault since a new unit was programed to the car?

The ECU may not be part of "Component Protection", but it sure has to be matched to the Immobilizer.

On earlier generation cars, it was possible to have multiple ECUs matched to the immobilizer and switch between them with impunity. I don't know whether that's true in the Mk.7. Ditto for the BCM.

-Uwe-