+1 on that. I can accept this as a possibly good idea if you were a doubler or just really forgetful, but that's still kinda freaky. I also have no idea if it's worth the $250 that the seller has it going for. It's the first one I've seen with the "integrated mouthpiece cap" design.
At least one won't lose the cap. But I can see how it would definitely get in the way while playing though I assume it flaps further back too and hopefully is tight to prevent it from flapping back and forth while playing.