Good on the guy. Too often are internet message boards filled with guys who claim to know it all and call themselves "experts"
Here is a guy who wants to know more about a certain subject and is actually man enough to ask us.
He may be a dirty little Celtics fan, but hats off to Brahmsian
Not to mention, that is probably the easiest defensive principle to get confused. Heck, when I coached high school basketball I would get the 2 mixed up sometimes.
Fortunately, there are few things that teenagers enjoy more than correcting adults, so my team was there to make sure that I knew that I had mixed them up.