OK, so the manufacturer says your shoulder bag is waterproof, but why put it to the test when a fifty-cent garbage bag is guaranteed? Pack a few in your camera bag and when the skies open up, just toss all your gear inside and tie it up until the rain stops. Carry a few extras and you can use them as rain ponchos just by tearing a quick head hole. You can throw them over lights when a quick storm rolls in, make them into impromptu umbrellas for protecting hair and make-up from getting ruined and even use them as a light-blocking flag if you use the thick, black kind. Not a bad resume for something so cheap.