I've just noticed this issue as well.
My locking issues with the 9700 just went from bad to worse. I have always absolutely hated the fact the top left key unlocks my Blackberry, but at least I could lock it with the side button, then use the old school *(phonekey). It was not perfect as the phone still always unlocked in my pocket, but it was way better than it is now since I can't use the side button for locks anymore.
I swear the the phone becomes less and less user friendly with every update.
If anyone has a suggestion/solution, aside from buying a different phone, it would be greatly appreciated.
KT