But, you still run the risk of being shipped widgets that will [combust|impale|disintegrate|other calamity]
Any random bin can contain books, food, electronics, jewelry, anything from anywhere as it gets picked from, restowed into, counted and recounted, etc. There's little room for quality control before items are available for purchase, because the system is optimized to get as many things listed on the site as quickly as possible. There are many ways in which the process could be made more robust, but it won't be because doing so would cost precious seconds.
The only way to avoid this is to by things only sold by 1 seller.
Pretty sure this has to do with the co-mingling people are mentioning which means you can’t be sure even if it’s coming from the brand.