Keep the screen from activating when the phone is in my pocket I usually use my phone without a lock screen, so I can start using it by just pressing a button. Problem is, the camera and volume buttons on my Motorola Milestone are really light, and are easy to press accidentally in my pocket.

Since it already has a proximity sensor, is there a way I can tell it to completely ignore key presses when the proximity sensor detects something? My intention is to keep it from activating the touch screen if I accidentally press one of the physical buttons while it's in my pocket.

EDIT To be clear:
I want the safety of not activating my phone when it's in my pocket, and I want the convenience of not having to go through an unlock-the-screen step when it's not in my pocket. 

It might be asking too much, but I thought I'd give it a try. I've read that Tasker might be able to achieve that, but I don't really know how it works and have no idea if it supports that functionality.
Tasker can switch on/off the lock screen and can trigger events based on the orientation of your phone.

So you could set up an event in Tasker that enabled the lock screen when your phone is oriented vertically but upside down, then always place your phone in your pocket that way up.