Of course they can. Those kinds of developers cause problems constantly. It's one of the biggest reasons we have code reviews. Automated tests help too.

But even with all of that we still have bugs and broken workflows. Now take that human and remove most of their ability to reason about how code changes affect non-local functionality and make them type 1000x faster. And don't have anyone review their code.

The code is the spec, someone needs to be reviewing it.