"(13)(a) Hazard lights shall be used for the purpose of warningthe operators of other vehicles of the presence of a vehiculartraffic hazard requiring the exercise of unusual care inapproaching, overtaking or passing."
-- Oregon Vehicle Code

What the driver thinks hazard lights are for:

"I'm not supposed to park in this yellow/red/blue zone, but I'm only going to be a minute. I'll put my hazard lights on, so should a cop or metermaid come by, they'll know I'm just popping in for a sec. I mean after all, who would leave their hazard lights on if they were going to be a while? It would drain their battery! Surely the cop knows this."

What the cop thinks hazard lights are for:

"Hey, look. There's a car parked with its hazard lights on. They must be parked illegally in a yellow/red/blue zone. Now that I've noticed them, I think I'll write them a ticket."

This is a roundabout example of how the designer and the manager should never be confused with the end-user.