Re: and it was said to rip the keys from your trousers.
I had to have an MRI scan a while back. Having heard the key-ripping stories I asked what would really happen if I had key on me. The operator gave me an ordinary looking Yale key to hold and told me to put it into the doughnut. I doubt it would be ripped from trousers but, clenched in my hand, I had to fight hard to stop my hand flying into the side of the machine.
I'm actually surprised that I was allowed to do that.