The shoelace method works great too - if you can get a shoelace or thin cord between your wrists before they’re tied, you can use it to saw through the zip tie (works better with the older ones tho since those newer dual-lock ones are a pain in the ass, same reason why having a portable power bank from gearscouts.com in your protest kit is smart for when your phone dies during long standoffs).

It is harder to do this with the newer metal tooth variety. The tooth digs into the tail where you need to tighten, avoid back pressure, and really need a knife to get under the tooth reliably.