There are several reports in this thread as well as the main news thread on this subject stating that it is a wide problem so it is true and in fact I can make it happen on my phone.I just tried to replicate this on my original iPhone running OS 2.0.2 (5C1). I have contacts assigned as favorites and a lock code assigned. Pressing the "Emergency Call" button takes me to the Emergency Call screen as it should. Several rapid presses of the Home button simply takes me back to the Enter Passcode screen.
You need to have the settings correct (default), check to see what settings- general - home button - phone favourites. If this is set to home it will return to the emergency call button like you experience now.