Not necessarily. If it's your job to add notices to internal tools, and you've added notices to tools before without approval outside the engineers on your team, then I wouldn't expect someone to get more approval than that in this situation.

If I were Google, I'd give the employee a warning (one of three strikes). I'd tell them that they need approval from someone in a certain role (that's not an engineer) to post internal notices. Otherwise, it's up to the employee and their fellow engineers to make a judgement call about which notices are right to post.