I like to harass the higglers myself, last trip the first one that saw me asked if it was my first time. I actually recognized the guy so I started yelling at him for not remembering me. Worked well. Another guy who hangs by our hotel kept harassing me to buy drugs from him, so every time I saw him, I kept saying, "hey, have you seen xxx?", which is his name. Throws them off guard and gets a good laugh.