Get off my lawn!

Cyrozap suggested a Kinect could help a ‘bot someone stepping on the lawn.  I don’t think it would be extraordinary to build something that would aim and operate a hose.  Bonus points if I could get it to look like either (A) a scary sentry robot or (B) a big Santa Claus.  Ideally, it would offer a warning, “Hey you kids!  Get off my lawn!”  And then a warning shot, just a wide spray – not intended to actually soak anyone.  Then, if that doesn’t work – a directed spray.

And, then, well, there’s always the nuclear option.  The ‘bot could turn on the sprinklers.