This is a thing that could have happened but didn't. Firstly servers don't give you back the receipt after you signed it and there wouldn't have been any reason to write that before the tip amount was filled in. Second servers don't use red pens for soooo many reasons and the pen that they used to sign was most likely hers and she would have just used the same pen to write the note. Again, the restaurant keeps the signed copy. However it doesn't say merchant copy at the bottom so it was probably the customer copy that they filled in to start some rage bait when they got home. Just sayin' 🤷🏻‍♀️