Statistics can be handled very naively by folks who don't make sports book software.
Yes, nominally there's a 1:100,000 chance of getting 000:00 on the end. (Or 1:1,000 if you forget cents.)
So that applies to the pool of IRS returns.
Every return is subject to a number of positive or negative amounts by the regulations. There are probably on the order of ten of these. All of those are round numbers. Every return is subject to these. This completely changes the naive bookmaking approach.
I am reminded of this Richard Feynman quote. "You know, the most amazing thing happened to me tonight. I was coming here, on the way to the lecture, and I came in through the parking lot. And you won’t believe what happened. I saw a car with the license plate ARW 357. Can you imagine? Of all the millions of license plates in the state, what was the chance that I would see that particular one tonight? Amazing!"
Whilst that is a wonderful Feymnanism, if Feynman was here he'd instantly point out the mistake.
If (particularly if I'm in Kansas) I saw a plate "CHIEFS15" or "PAT 015" it would be very naive to then say "As in Feynman's great explanation, humans naively see patterns where none exist."
"PAT 015" could be a sheer coincidence (and you'd be correct to use "1:1,000" type logic there) but there are other gross and blatant factors involved, which statistically drastically outweigh that approach.
It's almost certainly the case that