How to stow a bobby pin on a belt loop: https://twitter.com/mygauzeborn/status/1268058644739796993
https://lifehacker.com/open-zip-ties-with-a-broken-bobby-pin-1843882788
(If you don’t have a shim stashed, you can also tear a soda can with your bare hands. It’s not as safe as scissors, and whether you can do it with your hands in ties behind your back without anyone noticing is another matter, and being given or allowed to keep a can is probably no more likely than you being allowed to keep a multi-tool. If you do have scissors and/or pliers, you can skip straight to “snip the tie” anyway.)