If a restaurant delivery driver gave you the WRONG order which far exceeded what you had purchased, would you still accept and eat it?

No, probably not. 

Not if i knew the driver would have to pay for it. Those guys have bills too.

I would tell him it's not my order and not accept it.

Delivery drivers use their own cars and gas and they aren't paid much so you need to say something

That’s happened to me.  When I called the restaurant to let them know, they told me to keep it because they couldn’t forward the food after it had been given to someone else.  They just chalked it up as a business loss and made the order again for the right customers.

I doubt the driver would have to pay for it, although they might have that policy.  That’s something every driver should know ahead of time before accepting the job, for sure.