To make sure there was an improvement with reluming, the modder could for example shoot several reps together. The modded one should glow more than the others.
With lume or whatever else, the one who wants to cheat you will manage it without problem : Photoshop can completely transform your watch, independantly from your camera settings.
At the end, only the reputation of the member can help you. Don't believe all what you see, and of course not all what you're being told.