Back in the day when we used to fill out the Inward Cargo Manifest there was a box for "Master Person in Charge" which was the driver. While we're not being told to 'press hard you're making 5 copies' anymore... once the drive moves that loaded truck he/she is on the hook for ensuring that it's moving within the laws of the land. You can't roll in to a scale 5000 Lbs overweight shrug your shoulders and say that's how the shipper loaded it. While the DOT may (or may not) listen to the drivers story... the citation will still be made out to the driver and/or carrier.
Well, that's why Carriers need to start charging Shippers shit load of money for layovers, loss time, rework, detention anything they can in order to educate shippers about weight distribution.
The problem that I run into a lot is with custom paperwork because shippers always missing info like Tax Id for the customer, Quantity, wrong importer of record, forgot to send notice to customs brokers all the bullshit. well, what we do is put it INBOND and that's easy $500 minimum.
I have strictly told my drivers do not move until you feel comfortable with the weight and everything and if you pass the closest scale and realize its overweight then it's driver's fault and we charge the driver for getting the rework done at the nearest cross-dock and of course, we advise the Broker about the screw-up.