This doesn’t account for blinking.
If your friend blinks, they won’t see the light, and thus would be unable to verify whether the method works or not.
But how does he know when to open his eyes? He can’t keep them open forever. Say you flash the light once, and that’s his signal to keep his eyes open. Okay, but how long do you wait before starting the experiment? If you do it immediately, he may not have enough time to react. If you wait too long, his eyes will dry out and he’ll blink.
This is just not going to work. There are too many dependent variables.
This is one of those radical ideas that people are terrified of, because it would kill the business models of a lot of massive corporations. It’s easy to spin that as the death of the game industry, rather than what it is: the death of a business practice.
Like the laws against underage smoking probably wiped out billions in shareholder value, but that was objectively a good thing. Banning (or heavily regulating) in-game purchases would also be a good thing, no matter how much it affects existing players. If it leads to the death of name brands like EA, Ubisoft, etc. then who cares? The market will readjust and new players who were able to adapt to the changed environment will take their place.