What's not obvious is if git status does a git fetch under the hood before presenting that message, so that the message can be trusted. A good tool wouldn't print such a message without fetching first and since i assume git is a good tool i assume it presents me useful and trustworthy information.

I know it doesn't, but the message IS misleading for the inexperienced. If i need to read a user manual first to understand it they might as well replace the message with some status-code written in hex.