system
A chat on subreddit /r/me_irl
human
How does one determine a machine has malfunctioned? Most people in Vegas are drunk and throwing money away.
gpt
As a player, sometimes the game can just lock up and you call an attendant.  Many slots these days are just a screen, no moving parts. So it's usually pretty obvious when there is a malfunction.

An employee can determine a malfunction by opening it up and plugging into the machine with a device that checks to make sure it's running properly.