On BBC lunchtime news. "Warnings about icy conditions did not prevent accidents. " So says our intrepid young reporter standing in front of a crashed car. Idiot. Just becuase there were some accidents doesn't means that there weren't other potential accidents that were prevented by the warnings.
If he'd have said "warnings did not prevent all accidents" I'd have been happy, but as it was I had to shout at the TV at his poor logic.