I used this technique on an auction site once. It allowed the script tag in my username, so I used it to remove the "bid" button once I had bid -- nobody behind

I used this technique on an auction site once. It allowed the script tag in my username, so I used it to remove the "bid" button once I had bid -- nobody behind me could outbid me. It went about as well as you would expect using it for fraud. Which is to say, not well at all (；´Д｀)