Insertion of false information into articles
Thanks for experimenting with the page List of real tennis world champions on Wikipedia. Your test of deliberately adding incorrect information worked, and has been reverted or removed. Please use the sandbox for any other tests you want to do. Take a look at the welcome page if you would like to learn more about contributing to our encyclopedia. Thanks. 
Please do not deliberately introduce incorrect information into articles, as you did to Billiards. It is considered vandalism. If you would like to experiment, use the sandbox. Thank you. 
Please stop. If you continue to vandalize pages by deliberately introducing incorrect information, as you did to List of retired professional American football players and List of male boxers, you will be blocked from editing Wikipedia.