Even when clipped, our grey HAS flown into our ceiling fan. Happened a couple of years ago. It was running at a good speed and I thought it would kill him, but he seems to be resilient and somehow survived it without injury. I no longer run the fan while the bird is out of his cage.
He has also flown into windows and walls. Clipped or not, greys are clutzy flyers.
In a park in my neighborhood, I have seen a guy walking his dog with two mccaws perched on its back. Everyone gets a big kick out of it, but it seems risky to me. I frequently see people walking through parking lots going to Petsmart with birds on their shoulders.
Ron Kershaw Phoenix, AZ