in your scenario...why did Google wait until well into 2009 to add anything like Slide-to-unlock to Android?
Considering the codes can be completely and utterly different yet something can still infringe on a software patent it wouldn't take anything more than seeing something to mimic it even remotely....stealing wouldn't even be necessary...especially over 2 yeas after the public display of the feature at Mac World in 2007.
Also it wouldn't matter if Google had a cute lil slide to unlock thingy on some prototype device in the year 2002 unless they had ample evidence of when it was created...remember the software patent wars didn't really become as exhaustive as they are until relatively recently. A lot of things that COULD'VE been patented probably weren't even thought about when it came to patenting. "Pulling an image from one area to another area to initiate an unlock action on a screen" wouldn't have crossed many people's minds as a patent.
Apple played the game properly and now we have people arguing over how something that doesn't look like something and doesn't really work exactly like something is a total 100% stealing of something.