I haven't heard it either, but that doesn't necessarily mean anything. I still find all sorts of little tid-bits whenever I read something new.
Sometimes a little "factoid" might be fictitious, but represented as fact in a single book, and then it becomes a rumor with a life of its own. Or, it could be just a little-known fact.
Not all of the jousters are real historians, so I wouldn't take it as fact until some documentation can be found.
Now I'm curious. No idea where to find out about it though.