Last three day backpacking trip, I set up my non freestanding Lightheart tent on my patch of flat next to the creek on our second day out. My buddies were sharing an REI Half Dome "freestanding" box kite. A gust of wind picked it up and rolled it away toward the creek. It wasn't even windy, just a little breezy, and it was a good thing one of them was at the creek filtering water to intercept it before it swept across the canyon into the trees.

Then there was the Morro Bay campground, full of 8 person Coleman Behemoth Tents with furniture inside them. Everyone was out kayaking while the tents rolled around in the wind, like huge nylon tumbleweeds.... My little 2 person tent had stakes on each corner and fortunately aluminum poles, since one of the massive tents ran over it!

I don't believe freestanding is necessary.