If the code is really simple, it's cheap to read it. When people don't read it (and when they need to use "fleets of agents"), it's because it's not so simple, and then the people who trust the outcome are those who don't know what it is that they've committed into the codebase. Their logic is no more than: the system hasn't collapsed under the load of 50 (or 500) changes so it probably won't collapse under the load of the next 500 (or 5000). Because that's how engineered systems work, right? If they're fine under light stress, they're fine under heavier stress.