That quote from Matt makes me think of a developer I used to know. He put a time bomb in some of the old code just in case he ever got layed off. He had to reset it every month or so to stop it from going off.
He always thought no one would ever be able to find it or determine what it did.
Not that you necessarily were implying this, but that wasn't what Matt was referring to. He was referring to the fact that half the time the programmers were altering the code, they didn't always know why previous developers did what they did. Then the next guy would make changes, wondering just what the heck that guy was thinking when he did what he did. To understand the codebase, you didn't need to just be a programmer, you needed to be an archaeologist.
Back around 2010ish, I believe, the players started to post about yet another one of those crazy conspiracy theories about how the game rewards were rigged in a particular way. Except I started to get a weird jibe about this one, and started following the discussion carefully. Based on the tests the players were posting, there was no way random chance could have accounted for their observations, all but eliminating observer bias. So I began collecting my own data and adding it to the data being posted, and started talking to pohsyb about those observations, emphasizing that in my opinion, this particular problem (rewards sometimes being given in nearly identical amounts in similar ways in multiple runs of the same mission) was not just another "accuracy is nerfed" threads. He decided to look, and discovered that deep within the code of the reward system one of the developers had
written their own random number generator rather than use the standard rand().
Why, why, WHY? Who knows. But they did, and it was totally broken, and under certain circumstances could generate "random" results so bad they essentially made certain mission rewards predictable. Which, in an MMO played by dozens or hundreds of people at a time, is a *really* bad rand.
Now imagine you have ten years of that lurking around, mixed in with code written back when 8 gigs of ram was a really big server and bit-masking was the official Cryptic Studios sport.
You know how you can spot the Cryptic/Paragon developer in a crowd? Yell "physics engine" and see which one ducks.