So you require them to install a new circuit which might end up costing hundreds or even thousands in repairs to the house to get the circuit across the house. The homeowners will probably just say forget it we don't want the receptacle and wait until after the final inspection and add the receptacle themselves. They will then tell their friends and neighbors what the inspector wanted them to do which will discourage people from getting permits and inspections. This is a powder bath (1/2 bath) so a hair dryer will probably never be used since there is no shower or bath tub. The inspector needs to be reasonable and work with the homeowner not just go be the letter of the code. There are thousands of homes with 15 amp circuits feeding the bathroom receptacles I don't think one more will be the end of the world.
Curt
