[Threshold]

There is a way, but it's an absolute datafuck. You would have to loop through each individual character from A-Z, 0-9 and including symbols, 24 times over for each character to see if the file exists. If it exists, change the variable to 0. So in short terms, don't do it. Either that, or you create a ban log, get the server to loop through the text file contents, and search for the contents line by line with the usernames. Then edit that user file. Again, it's a big time waster though..