In addition to the reasons already mentioned, I had a friend who was a Sargent in Operation Enduring Freedom. She lost some of her buddies over there & takes the US flag very, very seriously. I was on a trip with her & another friend once and our mutual friend brought a blanket that closely resembled the US flag. My friend (the vet) was constantly concerned about the blanket getting perilously close to touching the floor. A real flag must be burned if that happens & she was conflicted about whether she would have to burn our friend's blanket if it were to touch the floor since it looked so real.
If you want to do something flag-themed, I would either just do some small blocks that somewhat resemble flags, or else make it very stylized so that it's clearly patriotic but readily distinguishable from an actual American flag.