One must assume the QC person is knowledgeable. Likely it is someone who was assigned the task by a manager and also likely knows nothing about how a bicycle is assembled.
We, the shop where I work, get a share of bikes bought at local big box stores that have been assembled incorrectly...usually loose parts, out of true wheels and now/then the fork is backwards...that always gets a hoot of laughter. I've also seen and dealt with pedals incorrectly installed, stripping the teeth and making the pedals/crank damaged beyond repair...not going to spend a couple of hours trying to repair a $25 dollar one piece crankset.
But it is hard to deny the attraction of buying a 20" kids bike at the local wally world for $78...I was at ww a couple of days ago and walking past the display noticed the bike and price tag...a great price for a bike that is likely to get trashed, left out in the weather 24/7, etc.
I generally don't have a problem with big box bikes as they generate a lot of service work for the average small shop and can be the gateway bike, hehehe, for something better when we show them the differences between bb and shop bikes especially when they take them for a ride...sometimes we get a 'rider' out of the experience.