Great Xia Jin is a human being, so naturally there are omissions. It is true that Master Jin made a mistake here. The ancients were also very wise. People who receive darts should show their certificates, then sign their names, and then they can take them away. It's not just a sentence or two written in a TV series or a novel. In case of an accident, someone should be responsible.
Martial arts novels, even Jin Xia, are inevitably ignored. After all, a so-called "Jianghu" is a virtual world. Just look at this kind of thing, there is no need to delve into it.