Let me make sure we are talking about the same thing because it seems like we are not.
Lets say that the OP needs to install a wire (sounds like this might be a remodel situation) that must cross a stud. Now for some reason it is not prudent to drill a hole that would have the required 1 1/4" clearance on both sides or that the stud is too shallow. So he wishes to notch the board. He then drills/cuts a 1/2" deep, 1/2 wide notch across the face of the stud(preferably perpendicular). Now to protect the romex he must provide a "nail plate". Now lets say that the added thickness of this plate will cause a defect in the surface of the final finish. He needs to somehow eliminate this bump. Now in the trade we just smash them a little bit harder so as to sink them in to the wood. Now say that this wall is to have a level 4 finish on the drywall that is not going to be enough. So is might be wise to router out or chisel out the additional thickness of the plate in the plate's footprint.
I still say just smash it!!!
Ragged Trousered Philanthropist
Please follow the code - its there for your safety no matter how inconvenient.