I'm disabled, so I can't speak for anyone who works as that is not my expertise. But I've shopped at Best Buy a couple of times, and one time I really was drove up the wall by the constant sales pitch of a warranty or getting people to buy a bunch of accessories where they did not need them. While the whole market of big electronic items is dependant on the manufacturers who make these things to complete our purchase, some of up already have the cables, but its hard to get out of the store because a sales associate goes on and on when you politely tell them no that you do not want the extra accessories.
So my idea is " No means no " when it comes to the sales of an item. If Best Buy was right and I was wrong, I gladly don't mind making the trip back to the store to get what was missing. I just don't want to come off across an employee in the store as "I don't know what I am talking about " kind of person if you get what I mean.
And hey its understandable, we all can't read body language and determine what someone wants, or knows , or perhaps not at all?