That's a real problem, and quite common. I think it's important, when confronting or correcting someone doing that (whether they're your employee, colleague, superior, team lead, etc.) to emphasize that they're not being punished or thought poorly of because of their ingenuity or initiative, but because they're wasting time and need to stick to the plan. Otherwise, initially headstrong but very capable people are often ground down before they have a chance to get used to the roadmapping/planning/etc. process at a company. This is especially true with new engineers.

I have no idea if the GP post you're replying to is someone rationalizing being in that position as being "disciplined for touching the wrong code", or whether something actually screwy was going on. I just wanted to mention that distinction because it was important to me when I started out (if people had come down on me for having ideas, instead of for wasting time, I'd be in a much less useful, happy, and capable place today).

I have to admit that, as an engineering manager, this is exactly what I was thinking!