This may not be announced publicly but it is the easiest way.
I think the Chinese government is doing this and some governments might do that if things get out of control.
Afaik Google have to reveal their source code to other companies, would Samsung not try to remove something like this? They're the main innovation hub for Google and have a larger market in Europe (probably more than they can get from the US)...
Any cypher punk trying to prove a point would just dump the keys on the net and wait for everyone to start using them to access others' data... It'd prove a point again the government, this could also be done by operatives in ex security services who can sell their skills as PIs in phone hacking. It'd be something journalism will be back to buying up!