system
Given the following post, respond as if you're commenting on Reddit:
human
[eli5] How does cash betting work, like they do in the movies.

In the movies, when theres a fight or a game etc, sometimes there is a crowd of people frantically waving money and one guy is collecting it. The only example I can think of right now is in Hot Shots 2, the fight scene in the beginning. The "judge" guy starts the fight before he proceeds to collect money from the cheering crowd.

Ive seen that kind of betting in other movies. 

But how does that kind of betting work? How is there any oversight over who bet with what against who?
gpt
If the scene is filmed accurately you will see the people collecting money also have a small pad and pencil writing down info. When you first walk in you would be given a number or code like at an auction. So he would write real fast something like 21-$100/blue (or whatever they wanted to use to identify the fighters.

In most movies being more accurate would also slow down the action so its usually not shown correctly. It just wouldnt be as exciting to see the fighters standing there for 10 min while they collect all the info and money.