They wrote in plain text that the customers son's word had been taken over a word of a techie. So it's either pushing more to convince her, refusing service or playing dumb.

Sometimes lying is good. Like when a customer wants you to lie to them

Tech tried to tell them it was unnecessary, would take forever, and would be expensive. I'd agree with you if, for a second, the customer sounded like they wanted to drop the matter. No, this was the customer absolutely digging their heels in, and the tech did what they could to get an irate woman out of the store.

At a certain point, you have to just let people make their mistakes, and get out of their way. This is exactly how I interpret the situation.