That is a flagrantly absurd idea. In an age where realism (and "realism") is treated as sacrosanct and "darker and edgier" themes are still enjoying immense support, the inability to kill a mortal being that just-so-happens to be on the lower end of the age spectrum is going to stick out like the proverbial sore thumb. Program in (appropriate and reasonable) consequences. Hell, introduce an Alignment/karma meter. Whatever L does, it should be anything but that; having non-critical NPCs who would otherwise be susceptible to damage instead be inexplicably immortal is catastrophically immersion-breaking.
We also live in an age where whoever controls the flow of information controls people's attention as well and is free to propagate any agenda, including the moralistic harassment towards the developer who just wanted to make things realistic for the sake of your, or any other kind. Should we also romance kids as well? Should the game have a jail where you should spend 50 years to pay for your crimes of killing children? What are the appropriate and reasonable measures you've mentioned? Can you specify, because otherwise it is hard to correlate with your opinion. I came up with this idea not because I find it realistic, but because it is a sensitive topic that can resonate and finding a middle-ground should be the most appropriate solution. Is there any absurdity about it? This is not a rhetorical question, please humor me.
