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perhaps put a roll of quarters in one of your black socks. ;) or whatever the equivalent of quarters are in your country.
good if you need to do laundry or use a vending machine too.

Or I could use my camera as a weapon, it's very heavy.

And before you ask, I have insurance.

go with that then as a first line of defense, then you can smash someone good and get a new camera!

Sounds like a win-win to me!