A dealer should have already checked out everything before you get there. The PDI is for the owner to see that all is good. If the dealer knows that it will not be a completed deal if it is not right can go a long way towards changing the many complaints on new units.
If they try to hurry you don't stand for it.
Anyone who accepts a new unit without having the dealer conduct a PDI in their presence is partly responsible for any problems IMO.