The single greatest audio scam is without question the Nuance speaker sales pitch, sold in a few miscellaneous outlets across Canada.

They take you into this room, tell you about how Nuance makes "special imaging speakers", then proceed to play a bunch of Q-encoded CDs so you'll be "amazed" by sounds appearing in 3D space. Without giving you a chance to ask any questions, inspect the units, or actually test the damn things with your own music, the pushiest salesperson on the planet offers you the "deal of the century" by bringing the price down hundreds and hundreds of dollars. If you're smart enough to actually demand your own audition, the salesperson literally starts insulting you.

Everybody MUST experience the Nuance scam, for sheer entertainment if nothing else.