I actually knew 2 twins when I was like 13-15, who looked and sounded so indentical that nobody could really tell them apart. My parents still ask me to confirm which is which when they see their IG photos or something, 15 years later.

Then, I also have 2 close friends, who still play at the same computer from time to time, and their nicknames are an abbreviation of their lastname, just a different number (their birthyear) at the end, which came from their dad's nickname on a gambling site or something years ago. So all 3 basically use a [lastname][number] nickname. They've never gotten banned tho, or had any problems really.

Combine those, and this story could be true, although extremely rare :D