I've seen lots of animes where a character is caught and interrogated by some authority. The captive is usually depicted sitting on the chair in the interrogation room. But instead of being handcuffed, their thumbs are tied with a zip tie.
Why? Is there a meaning? It's so weird! Is it common to use zip ties to restrain criminals in Japan? I'm confused.
No this is not some kinky anime; I don't watch that stuff, it's an action based anime, more specifically, AICO incarnation or something like that.