Why would you and your brother be talking to each other in the forums? Can't you do that at home.
Rich probably thought you were the same person because you both have the same avatar (somewhat) and your names are also almost the same. Now, if your both using the same computer then the IP address for both accounts would be the same and Rich could assume that both accounts are you.
But I'm sure you already knew all this.
Scrotal Safety Tip #3: Purchasing a swimsuit with built-in underpants will greatly cut down on excess scrotal-stress during a spirited game of volleyball and the like.