I had a Canon G7 that I kept in my coat pocket and never had a problem with it until I tried to sell it on Ebay. I tested it beforehand, but omitted to try smaller apertures (out of habit, never having felt the need to use them). The buyer did test the smaller apertures and the sensor was covered in dust! Fortunately it was all dealt with via an amicable refund. But P&S cameras can fill with dust easily. I now use a little neoprene pouch for my Canon S90, bought from a hiking shop and sold as a waterproof mobile phone pouch, perfect! But beware not to take as gospel the mantra 'pocket camera', it may need some further type of protection!
Steve