Don't get me wrong.. I love the idea.. However without any structure tying it to the ground it is simply an airfoil. As the wind blows it will want to spin due to the differential air pressure. You could use hiking poles to secure a single side or opposite corners to the ground and I think you could say... Problem solved.
... Then again, in very high winds, say something like 30+mph, an airfoil is an airfoil. It will want to 'fly'