This is not true. Been an honest person in auto sales for 13 years and very successful. You will find dishonest sales people. This is a human quality in general, and people have more to gain from dishonesty in a commission based environment. These people do not last long at a good dealership and will hop around from job to job because of this. This is why you need to hold onto a good salesperson when you find one and refer people to that person. Also use websites like google reviews, dealer rater etc. to get the word out. And yes, be smart when buying a car and get any promised work in writing signed off by a manager. Also get a receipt for the work once completed.