The Griffin case is an exceptionally good piece of kit with one drawback. Anyone who owns one of these will no doubt regale you with stories of pocket dialling all and sundry whenever there is pressure against the case. This happens because the voice control cannot be deactivated in settings on the iphone 4. A quick fix for this is simply to turn the case inside out and use a Stanley knife to remove the protruding rubber nipple. This means that you actually have to apply pressure to the button in order to use voice control or unlock the device. Doing this has made the case near perfect, if only it were submersible. hope this helps all.
BTW If anybody knows of a way of turning of voice control on the iphone 4 please write something about it.