IMO, there's no point to NTR (NTR here is protagonist's "girls" get stolen from him, netori wouldn't pose an issue for most people as it's the protagonist doing the stealing) if it's not the main theme. Good NTR needs setup, establishing the relation between MC and the girl, and then the corruption/stealing of the girl. I don't see how a quick dirty NTR can happen, not without simply destroying the character (instantly in love with NTRman's dick), or some cheap crap like mind control. But then again, for someone who likes NTR, why would you play this game for a single/maybe few scene of NTR? Why searching crumb when you can play an actual NTR game? I don't get it.
That aside, would people consider NTR if the girls get raped? Girls don't enjoy it but still get fucked by non MC. Suppose some people want to see girls getting some ghost tentacle action, or maybe some ghostly dog for bestiality. Just plain sex for the pleasure of the player but has no impact on the story (girls/MC just brushed of the whole thing and isn't mentioned ever again).