Anyone ever consider that cards, letters, etc. are a waste of time because there is still an alarm to be resolved?

What is the difference if a hip sets it off or a gun?

Same alarm in the same place.

Simply resign yourself to the laws of physics and try to keep extraneous metal in your clothing to a minimum. Tell the screener you have a hip/shoulder/knee before you go through the metal detector and hopefully you'll be through in no time.