Brakes are big part of ratings, sure you can haul 2000lb but it wont
stop well, get in an accident thats your fault and your weight could
be a charge of negligence.


True!

FYI - 1/2 ton means nothing! I had a 1/2 ton with a cargo weight rating of
800 lbs. The same truck with different factory options could carry more than
1/2 ton. Depends on how the truck was ordered and built!

The weight rating can be found on a label on the driver's door or in the
glove compartment typically. This is the weight rating for THAT specific
truck.

The weight rating is not just how much weight the truck can hold, rather it
is how much weight it can hold and still be driven SAFELY. This means
braking when going downhill (and not having the brakes fail), turning
corners and not rolling over, being able to suddenly brake and turn to avoid
a kid running out in the street, etc.

Also if you load a vehicle with too much weight, the wheel bearings can get
wrecked. Axles, bearings, wheels, and tires have weight ratings as well.