My brother is an engineer at Boeing... he claims that this is the most screwed up engineering project in terms of cost in human history. I think he has a point.
I'm an engineer at Pratt & Whitney. I'll have to say that may be close, but Star Wars takes the cake.
I've done it myself, I have a Blackberry pearl 8150 (I think). It's not hard to do, if I press a button while the phone is locked it pops up a menu to either unlock, dial emergency, or cancel. So in order to make an emergency call, I have to hit a button on the phone (any button) twice, once to de-idle it and once to bring up the menu, then the little ball chunk needs to be scrolled down to highlight the second choice, then either the ball or call button gets pressed. I got a phone call from a number that had about 16 digits that came from the local P.D. asking if there was an emergency and telling me to reset my phone.
I don't know how the iPhone works, but you don't have to unlock my phone to make an emergency call, that's the one thing it will do if the phone is locked.
Basically same story from me, however I figured out (the hard way) that on many phones dialing 08 is an emergency call to 911. Why... beats me. Its very easy to accidently hit 2 adjacent numbers at the bottom of my phone in sequence and then hit the largest button on the phone (the dial button) afterwards and not notice until you get an irate call from a dispatcher...
You can't go home again, unless you set $HOME.