Customer experience and service is key. If there is no one available to assist in the Microsoft section (see: Surface Book), then someone with knowledge on that product needs to be made available.
And when the line for the lone checkout exceeds 10, provide other lanes open. And when that lane does open because I have to tug and pull on associates to open more lanes, do -not- critique the customer (myself) on being "rude" when you can't do your job adequately.