No, code wouldn't have to be re-written for this change to be made. Any programmer that would hard code these types of configuration settings is a pretty crappy programmer. I would wager it was something as simple as a check box either accidentally or intentionally being selected/deselected or a Boolean operator in a config file being changed either by design or accident.
It really isn't uncommon at all for someone to make a change in the live environment they meant to make in an off-line environment or to change the wrong option by accident if it was, indeed, an accident.
Yea I agree this really depends on how the server side interaction is setup.
I imagine this isn't an issue in code, this is probably an issue with options selected through the server interface.
I imagine the code is set up to allow a multitude of flexible options. 1,2,3,4,5,6,10 Fast Passes per person, Tiers on, Tiers off, hard limit 3 FPs, Extra FPs after 3 are used, etc etc, Set parameters over time. Select X options from DATE until DATE ... etc.
This might just be the result of someone clicking the wrong box, or not setting date restrictions to options etc.
This really depends on the separation between operations and management control and hard code. But I really do imagine the scenario is something like what I have laid out, where coders are setting up a system for park/operations management to be able to interact with without requiring additional code.