I'm also curious to see if the robbers get caught that it turns out they found out knew she regularly left too much in the till, and that pattern factored into the initiation and timing of the robbery.
Or the robbers knew that the night they chose was the busiest night of the week, and therefore the night most likely to yield the best returns - with no particular knowledge of the manager's practices regarding the till?
I am not privy to the criminal psyche. Is it normal to case a fast food joint that intimately, in an effort to get $400?