It's probably an argument that would revolve around proving that you (the customer) was not mislead because you knew it was an error. All the same, it becomes a fight over facts. At $20 I don't think it's at all clear cut that it's an error. Maybe at $1 it would be. Remember as well that includes likely to mislead, which isn't the same as proving that you were misled. And misleading conduct isn't the same as deceptive conduct. It's a pretty wide section, which is why it's probably one of the most litigated section of legislation. Have a look at Parkdale Custom Furniture v Puxu in the HC if you're interested, one of the first significant cases on this area. Lockhart J in the FC made some fairly strong statements in later cases that would cite that which should be fairly easy to find.