Where I work, the standard for new car deliveries is "reasonable perfection." The car is rolled into the showroom for the delivery process where the salesman spends about an hour going over the vehicle functions with the customer. The car is cleaned to a very high standard and the customer is encouraged to inspect for any defects before signing that the car is fine. A test drive before signing is not usually done but wouldn't be denied if requested. I have never seen a car make it all the way to the delivery stage with a defect so serious that it would justify terminating the sale. However, the point about vehicle complexity is well taken and I have come across the odd esoteric function that doesn't work properly. For example, I do recall a car where the speed/volume compensation function of the radio didn't work. As was said above, problems like this are fixed with under warranty.
As an aside, one of the most common complaints after picking up a new vehicle is from hypersensitive new owners believing that the car pulls to the left or right. When the car is brought in it is determined to have perfect alignment 99% of the time. Interestingly, Ford has reported that steering related complaints dropped over 50% with the introduction of the electric power steering system on the 2008 Escape that automatically detects and compensates for road crowning that is often mistaken for bad wheel alignment.
I would definitely spend a few minutes looking at the paint. But spending 45 minutes? At least where I work, between the PDI technician, the detail shop, and the salesman in the showroom, the chances of a serious paint defect not being discovered are pretty slim. I guess it would depend on where you are buying and the quality of service they are providing.
