Neither article mention's what the proper response of the receiver of these goods should have been.
If someone told you Walmart was giving away all it's products, would you just go in and load up your cart?
I think the users of Craigslist are naive, much like new email users who believe every spam they receive. There were comments on the DallasNews site from readers to the effect of 'this should be against the law'. But it's not. There is no law against lying (outside of commercial product misrepresentation, lying under oath, etc).
Hopefully, Craigslist users will wise up soon. Get 'Bills-of-Sale', or at least determine the proper owner and get permission for 'free' items.