Here we have an umbrella with a functioning, realistic-looking water gun attached to it. I see no problems arising from this. "Hey, it's raining. Also, is that guy pointing a gun at us?" / "I don't know. Pull out your gun and point it at him." Couldn't they at least paint it orange? What if a bad guy with a gun comes in? Everyone is going to expect umbrella-person to save the day, but all they'll be able to do is apply a light mist.
I am very happy they included the water gun function though. I hope it loads through the top so that you can just keep shooting as long as it keeps raining. You know Rambo? You could be Rain-bo. That might not be the toughest nickname considering it sounds like rainbow.