They had the hazards on.
Definitely good, but people ignore hazard lights all the time. If you have lights or flares to designate a bit of a wider path, 99% of drivers won't drive over flares or such.
Please don't take this as me saying that this is in any way your cousin's fault, because it 100% is NOT. I just want to use this opportunity to stress how important adding something small in your vehicle can be.