Maybe, but it doesn't just use it to signify that it's made a mistake. It also uses it in a positive way, such as it's had a lightbulb moment. Of course some people use expletives in the same way, but that would be less common than for mistakes.
I think you're onto something, however, as the training is done through on text and not actual thoughts, it may take some experimentation to find these stronger words.
