This is an interesting topic, and thanks Hope for the quote.I don't think that's what it means. What "hasn't taken reasonable care of the goods" mean is the returning an item in a state that's poorer in condition than the state that the customer received it.
"The DSRs allow consumers to examine goods they have ordered as they would
in a shop. If that requires opening the packaging and trying out the goods then they have not breached their duty to take reasonable care of the goods"
Trying a card in your machine is not examining the goods as you would in a shop, so I don't believe you'd be covered if they knew the truth. When it says "If that requires opening the packaging and trying out the goods" that's comparible with trying on a jumper, not testing a graphics card.


