JW you made me gringe!
I'll amend what I wrote -
In addition to buying the QR plates with the little screws, also get the head with the good QR - the one where you have to push a little lever with your finger and then the large lever with your thumb to remove the camera.
Or wear short sleeve shirts.
If your camera is really big you could use a quick release system made for movie cameras. There are quick releases made that can hold a 50+lb camera in any position.
I used these hex plates for 25+ years with no problems for everything from 35mm to 8x10 Kodak.
Get the plate with the big screw instead of the thumb screw and tighten the little set screws.
I have never had one come loose even when carrying an 8x10 on the tripod over my shoulder. These work if used properly. I leave them on my cameras at all times and never take them off.
Recently I switched over to heads that use the RC4 qick release plate. I switched because I am going lighter and more compact wherever I can without risking safety and stability. When I switched, I mentioned to my assistant that these were more secure to which he laughed saying in the ten years he worked for me he had never seen one come loose or have a camera fall off. He finds my rationalizations for buying new equipment rather humorous and phony sometimes.
"Vocation to Solitude -- To deliver oneself up, to hand oneself over, entrust oneself completely to the silence of a wide landscape of woods and hills, or sea, or desert; to sit still while the sun comes up over the land and fills its silences with light." Thomas Merton
My only experiance with a quick release plate wasn't a good one. I had a bogan tripod with a 6 sided plate quick release. It didn't secure well enough nor was the head on the tripod designed heavy enough for my 4x5 use at the time. I went to a manual screw system and a #5 gitzo low profile head. There are no accidental fall offs and there is no camera movement.
Try the plate shown in the lower right of this website. 030L. I use it with a Wehman, and it is absolutely stable. You don't have to tighten the corner screws unless needed to really lock it to the camera.