Haven't seen anyone talking about this yet, but it is an issue (I saw some stuff about it out on the web). My new 4 keeps activating when it's against my face talking and it will dial calls, end calls, hit the contacts, whatever. Some think it is a proximity sensor issue. Is this how the screen shuts down when you are talking on it or does it involve the accelerometer as well? It's done it about 15 times already, it's dialed about 10 numbers out of my contacts, about three of the times it opened up contacts, and two of the times it opened up the keypad and started dialing digits. Well, 'it' being my cheek or side of the face, whatever you wanna call it. It's annoying.