The Definition of a Sales Rep is TO SELL YOU products NOT to give you support.
If you don't like that I don't know what to tell you as far as Sales Reps. They get paid hourly as well along with that extra bonus for extra services. ALL COMPANIES DO IT!
So if the sales rep lies to you and you wind up with a package that costs you more it is your problem. Sales people lieing is not really a union/non-union issue. Although a lieing salesman will more likely be fired when he is non-union. The union will protect an individual, no matter what they may have done wrong. Companies giev their sales people scripts to use to sell their packages, and leave out information that a customer needs to make an informed decision. Then they tell the customer they need to sign up right now on the phone or they will lose the deal.
Interesting question, some people due to poor ethical upbrining are likely to lie with out incentive. Others may lie with a proper incentive. There are also people who will not lie no matter the incentive. Being union or non-union would not likely make a difference.