Because it's really loud and people are trying to sleep! Also have you ever tried running through a densely packed corn field? Not nearly as much fun as it looked like when Mel Gibson gave it a go in "Signs".
With nothing more than a barely working 3G phone (thanks Consumer Cellular!!) and a personal GPS satellite in space I found myself standing in full uniform in the middle of a field in Krueger's farm at Sauvie's Island. A dark limo carrying a bride and groom was greeted by the scurl (squirrel? I think you may be wrong, autocorrect) of the bagpipes.
To my surprise, the wedding reception was actually being held at a big oak tree nearby (pictured above) as opposed to the middle of some random field. Special thanks to Mary K. who agrees that bagpipes sound great anywhere, even in the middle of the field.
PS: Do not play bagpipes at nude beach on Sauvie's Island.
PSS: "Gentlemen, I bring you...CORN!"