Well you could have just posted this as a comment in the previous discussion. However, it does bring up the good question of how do you pass the blame around when something doesn't look right? You dont! No matter how many times you tested your algorithm, never assume it will catch a culprit with 100% accuracy and please don't make a program to accuse someone of something. It is embarrassing when you have a false positive and you accuse your paid customers of piracy or when a potential investor gets his email auto-returned accusing him of being a spammer.