Caveat emptor is the rallying cry whenever someone finds a nasty surprise coming along with a purchase. But I don’t think “let the buyer beware” really applies if you buy a product that, in addition to being duplicitous, might just burn your house down. Such was the case with one unlucky Reddit poster, who opened their new 500-watt power supply to find a conspicuous steel box inside. Once opened, the box was found to contain nothing but a plastic bag of iron filings. Other posters on the Reddit thread (spotted by Tom’s Hardware) immediately suspected that the box was included to add weight to …