I recommend you cut off part of your screen protector, or get a different brand (I've used the ones from the VZW store and they work fine, but they're relatively expensive). The sensor is roughly where the notification LED is, but on the other side of the speaker. If you take a picture of your phone with a digital camera, the IR beam usually shows up as a red glow. As for your cheek touching buttons.... It very definitely could. When I work, I sweat, and the pockets of my shorts get damp. This dampness, combined with the movement of my leg (through the material of the pocket) causes my phone to unlock itself, open various apps, change settings, and/or text random words to my friends. Today, it was "Coke Kiwi". These touch screens are much more sensitive than you think. Can I also recommend that if there is a number you call frequently where you input numbers (Voicemail+ password, bank+ account number + PIN, etc) that you save those sequences into the number, so that the phone dials them automatically? When you edit a phone number, you can add a p or a w from the options menu. P is for pause, and it inserts a blank of roughly two seconds. W is for wait, and it will wait to send the next sequence of numbers until you click something on the screen. Obviously, Ps are less work. You can have multiples, so you can add a few pauses to get around long prompts. I'd say that once you cut your screen protector (first, try going into settings and turning off in pocket detection, it's known to be buggy), you'll be much happier with the way your phone works. I know I enjoy mine. Hope that helps.
