So - say I create a program for, say a Tivo with a GPL3 kernel (big assumption, I know), Tivo's programs are guaranteed to be authorised, and I can authorise the program to run on *my* Tivo as well. Meanwhile the program I wrote wouldn't run on other Tivos without being specifically authorised? I can see that as having some utility...
Or a small number of keys that always work - which leads to your second scenario?
Am I reading you right here, or am I just being dense?