It does turn on in my front pocket if standing up from a sitting position. That's like 3 seconds of screen on-time times the number of sitting/standing motions a day while it's in my pocket. So if I average that motion (while it is in my pocket) say 100 times a day, that's only 300 seconds or 5 minutes wasted screen-on time a day. Hardly a noticeable hit on battery life, unless one it obsessed about battery life.
...simple solution to this is just to keep the phone in your pocket but upside down (charging port facing upwards). That way, the phone will not light up with any motion at all as it needs to be the right way up, for the 'Raise To Wake' feature to work.