Amazon track the packages very well... if the "part" was missing, Amazon will track down the person who packed it and have a few choice words with them...
While I was back in the states a few people told me of people bending the system as a way to make a few extra bucks...
For example... Shops that have a 70% discount now only allow returns for 3 calendar days... why? because people were buying up all of the discounted items and putting them on eBay before the originally allowed 30 days were up... if they didn't sell them in 30 days, they would return them for a full refund.
That's American ingenuity...
