Traveling to/from Mexico with batteries

[Merlin Rhoda]

A hard block scuba weight at the end of a weight belt would probably make a pretty effective weapon and may be able to crack a window in a plane.

So would a laptop battery, a broken off piece of a roller cart handle, a couple of rolls of quarters in a sock, a previous generation can light, etc. This approach of limiting anything from getting on a plane that could to turned into an improvised weapon doesn't work.