It's usually best not to make assumptions about people based on appearance. Generally, this is considered a bad move… while also being unethical. Plus, when your designs are dishonest, making assumptions about people's ability to recognize your deceit could backfire spectacularly. In this story, this scammer mechanic completely underestimated his customer because he deemed her to be an easy target, expecting a small blonde woman not to know all that much about cars. The thing is, both her broth…