We have had a related rule in the EU for a decade and a half: If a consumer buys an item from a professional, and the consumer complaints about a defect within the first 6 months from the purchase, then the assumption is that the defect was already there when the item was purchased.

So in other words, the burden of proof is on the seller to show that the defect was not already there when the item was bought. See article 5(3) in this directive from 1999: http://eur-lex.europa.eu/legal-content/EN/TXT/?uri=CELEX:319...

I think it has worked really well. This kind of rules are a great innovation in consumer law since they make it really easy for companies to know what they "are up against".