When I bought my Sega Mega Drive in a video game store, you got to choose one game and you would get one "secret" game. So I chose one game (Alex Kidd in the Enchanted Castle) and the store owner chose one game (some NHL crap). I was disappointed in his decision, of course, but paid the money and left the store. While outside, I opened up the NHL box and noticed that weird, larger cartridge that didn't even seem to fit the Mega Drive (the cart wasn't as wide as the actual cart slot). So I went back in the store, and said "hey, I think you gave me the wrong kind of game, this one doesn't fit the Mega Drive", and showed him the cartridge. The store owner was baffled and excused himself and gave me another game instead (Decap Attack, which turned out to be awesome).
Some video game store owner, ha ha ha! Didn't even know about those EA carts.
Sure, I didn't either, but ...... that's beside the point!