It's not only the phone application. The calender and the alarm has also this ui-design-bug. :-(

I've created a Brainstorm about this Bug. Please Vote and Talk here about Brainstorm related things.

At the Bug Report we've got the feedback from Nokia it works really nice. But thats wrong!
There must be a reason why HTC, Apple and even NOKIA itself are using swipe for answer instead of simple buttons. The 5800 had also only Buttons to answer. When Buttons on the touchscreen are so good when the device unlocks itself, why has the N97 now a swipe to answer action?