Okay, no, this isn't about policing, but it is about playing roles. Specifically, what a sales rep is (and isn't) and what a sales manager has to be when it comes to Customers.
If a Customer hasn't paid a bill, asks for terms that are above and beyond what the salesperson is permitted to offer, etc., who has to be the one to tell them that they're not going to get it?
If you said the salesperson, you're fired. (How did you even get this job, anyway?)
A salesperson never says no. Sales managers say no. That's a major part of what they're paid to do - set and enforce goals and limits.
This does not mean that salespeople always say yes, but what they can and should say, in order, is this:
"I can ..." and offer an alternative or, if that doesn't fly, "Let me check with my manager".
Managers are the bad guys* in this scenario. They have to be, because the sales person always has to be the good guy*. If they're not, why would the Customer ever bother talking to them again?
I'm not saying that the sales manager has to actually talk to the Customer every time some point of contention comes up, but the salesperson has to be able to say, "We will do X, but we won't do Y..." and know that their manager will back them up. The sales manager has to hire salespeople that they can trust (or train) to deliver that message in a way that ultimately leads to acquisition, growth, and/or no further pushback.
This means that the salesperson has to always say things in such a way that the Customer doesn't just try to go over their head to the sales manager. Otherwise, what are you paying the salesperson for?
You do this by agreeing in advance what the terms/boundaries are for each transaction (if not each client) and sticking to them, no matter what.
Remember: Customers like predictability/consistency. The road to that country is paved with boundaries that everyone knows and sticking to them.
* Please feel free to insert the pronoun of your choice.
