What do you do if you or one of your crew messed up and install 12 Ga romex instead of 14 Ga. in part of a 15 amp circuit? (This is in a new house).
It was just a 12/3 traveller cable between switch boxes in a 2-way switch circuit, but I had the guy pull it out and replace with 14/3. It only took a few minutes.
My reason was that, on the outside chance that an inspector notices, I don't want him worrying that maybe we're sloppy, and maybe somewhere else we used 14 Ga as part of a 20 amp circuit.
In this case, I wanted the new helper to understand the importance of "staying tuned" to what he's doing.
I'm going to try a tip I heard a while back, on jobs where I have a helper, to use different color spray paint to mark the 12 and 14 ga coils of wire, before we get out on the jobsite. Red for 12, yellow for 14, a few stripes from the inside to outside of each coil.
I would have left it in, it's not a violation. Taking it out only wastes time, and here time is money, especially on the rough side.
It's highly unlikely that an inspector would catch one piece of wire in the midst of an entire house. And he or she would probably assume correctly that your helper accidently used the wrong roll of wire. If he finds a 14/2 where a 12/2 should be, than he can say that you are sloppy.