Its a contentious patent to say the least. Especially as Apple has been taking advantage of the US Patent Office's sloppy governance to extend the original application. Especially as this is just an onscreen implementation of a real world action. That Microsoft had in Windows Mobile back in 2003.
I'm left to wonder why everyone is rushing to add an onscreen lock action when the most sensible, usable and straightforward is to hare a physical button which does both. Asus had this very solution on the XDA Zest and I've not found a better one since.
That's assuming you need to add a second action to the unlock process. Personally I disable the lock action anyway. And l've had no instances of phantom dialling yet.