well, they try to... *jailbreak* *cough*cough*

look at the whole itunes vs pre debacle.

the real question, I think is, would that UAE spyware snafu have happened if there was some transparency? I'm not saying the underlying code or systems should've been laid wide open for all to see (even google understand this distinction of private vs public), but that the chances of getting away with stuff like that may have been much reduced