Lots of manufacturers go for the wow! Factor when demoing their products. The big sound (or big bass) from a small speaker probably accounts for the curtain trick. Bose used to do something similar at CES. The fact that Magnepan does this at audio shows may say something about who Magnepan thinks they are demoing to.
BTW, MBL and its ear-splitting SPLs at shows are another example of the phenomenon, IMO.
BTW, MBL and its ear-splitting SPLs at shows are another example of the phenomenon, IMO.