User blog comment:Dopp/Technical Update: February 7, 2012/@comment-957747-20120212023454

"We're updating the default style for new tables created from Visual Mode for a more attractive look and feel. This will not affect any existing tables, and it will not impact editors who work in source mode. These new defaults (class="WikiaTable") can be easily changed in source mode or overridden with custom CSS. "

This statement is incorrect. It is actually  that is added to tables created with the table button in visual mode.

is also affected by the code change, but is not the class added when using the button in the module.