You don't think it has to be? Honestly, I don't know; I'm not in sales at all so this is my off-the-cuff opinion from outside, but it sure seems to me that the entire profession of sales is all about dishonesty. Whether it has to be or not, I don't know: how successful would honest salespeople be really? If the dishonest ones are more successful long-term, then that means that companies that use dishonest salespeople will outcompete companies that don't. I don't know if it's really like this (a scientific study would be difficult, plus it could vary a lot by industry; what works for Best Buy or used car salespeople might not be the case for enterprise software or medical device sales), but I do suspect that, thanks to human nature and short-sightedness, dishonesty in sales probably does correlate with long-term success. Maybe the internet with all the online reviews will change this, as it gives people more information in evaluating merchants ("John at this store totally lied to me when he sold me Widget X!! Don't shop here!").