Who said I was trusting the result?

There's a difference between being skeptical, and just being a contrarian. Saying you can't trust a tool because it isn't perfect, just shows you don't understand that no tool is ever perfect. It doesn't need to be perfect, it 's providing an additional data point for you to make a determination. That's why the tool gives a confidence score.

We know the sign exists in that location, it's on Google Maps. And I've personally seen similar phrasing on these types of signs in real life before. Given those two facts, there's little reason to assume the AI detector is wrong here, even if it's not 100% accurate. It's just one additional data point, and probably more trustworthy than a random online comment saying "it's fake, trust me bro".

People are stupid, especially random online commenters. How many times have you seen a comment that would look like it could be accurate to most people, but you have actual knowledge in the field and know that it is 100% wrong? It happens to you all the time, you just don't actively notice it because you don't have the personal experience in every topic to see when it happens.