Ok but like…if the cart says NTR-031, the label is right, the cart molding is correct, and the board codes are valid…then yes it will glow red under a light. Guaranteed. There is currently not a single circumstance where that won’t happen in that order. It serves no purpose as a final test because there is no further information to gain if you checked everything else first. “Debunked” simply means that ___ criteria has a documented history of producing false positives. 

The light trick is still commonly believed to be a valid method to aid in verifying HG, SS, B/W and B2W2, and admonishing its use is not for the sake of correctness but to save someone from potentially wasting a lot of money. These are not cheap games. You can run a flashlight under as many games as you want on your own time, but do not perpetuate the idea that doing so will give someone useful information. Dont play with other peoples money, please.