Lol....I was on the same train of thought as Momof4, hahaha! Some days, I'd be all over that like white on rice! Just kidding.....sort of

I always have water available during outside play in the back yard. I use the coloured sippy cups (not sure what brand). Every child has the same coloured cup at every single meal, snack, etc. This way, they're trained to use only their colour so I can just leave them out during outdoor play and they typically only grab their own cups. During indoor play, I don't find it necessary to leave drinks out but always, always, always during outdoor play. But they're not allowed to run around the yard with them. If they want a drink, they're to sit on the ground by the deck, then leave their cups on the edge of the deck before returning to play.