why do you think they make error hot wheels

[hotroader 0]

I HAVE A CLUE WELL THE PEOPLE WHO MAKE HOT WHEELS WANT THE HOT WHEELS TO BE MORE COLLTABLE THEN EVER .SO ONE PERSON IN THE FACTORY MADE A ERROR ON ONE CAR AN SHOWED IT TO THE VP SO HE LOOKED IT OVER AND SAID WEL THIS MAYBE WHAT WE NEED TO GET COLLECTORS TO BUY MORE . COLLECTORS NOW SAY FINDING A ERROR IS BUTTER THEN LOOKING FOR TRESURE HUNT WELL TO ME IT IS A LOT HARDER TO FIND A ERROR THEN IT IS A TRESURE HUNT HOT WHEEL BECAUSE I WILL STAY IN THE HOT WHEEL SECTION FOR HOURS SO HOW LONG DO YOU STAY IN THE HOT WHEEL SECTION MY WIFE SOMETIMES HAS TO DRAG ME A WAY FROM IT BUT I SOMETIMES COME OUT WITH SAME GOOD ERRORS MY ]FIRST ERROR WAS A CHEVLLE AN THEN I FOUND A BLUE RAM 1500 WITH WINDOWS JUST A MOUTH AGO I FOUND A MUSTANG WITH WINDOWS IN BACKWARDS THATS JUST THE START OF WHAT HAVE ITS NICE THAT THE FACTOY DOING IT. SO TO ALL THE ERROR COLLECTORS OUT KEEP LOOKING FOR ERRORS BECAUSE ONE DAY WE MAY FIND THE MOST RAREST ERROR OUT SO GOOD LUCK .

[musclemania 0]

Hahaha, you got your point there.
But at manufacturing point of view, it is just a production line error which contributed to the reject / defect.
Subsequently, it might be overlooked during the inspection, therefore finally it was slipped out to the market.
But, IF there is huge quantity and aware by factory, there might be decision to release it as "normal" if there is no major impact to the end customer (safety, health reason, for example). Else, there will be huge quantity to be scrapped.

It is not like 1:1 scale where factory produced with error and the defective car can still be released to the market. It is pretty tight under TS / Automotive control for safety reason, as well as customer's satisfaction.