It's not just for the inspector!! If you are going to run 12 guage wire in a lighting circuit, then everything in the circuit needs to be 12 guage 20 amp stuff, including the switches and lights! As a matter of fact, in your typical home improvement store, which 99% of the DIY projects will be purchased, you will not find a single fan/light combo that is rated for a 20 amp circuit and 12 guage wire! Heck, even the wirenuts they provide in the box are for 14 guage wire! Enlighten us as to why a common household lighting circuit would need a 20 amp circuit!!!
