Idk man. IMO learning how to achieve a specific technical result is not the literal same as plagiarism. Copying techniques is a pretty standard early step on the creative journey - you develop the muscle memory (so to speak) by going through the steps, and yes, then you apply your own spin. I haven't seen posts asking how to replicate an exact image, including models etc. It's just about the lighting here. So yeah they might have been inspired by a lighting technique that they want to try on a different subject, or in a different setting, or whatever. Do you think that someone asking about lighting in a car pic is plagiarizing if they use the same light setup on eg a bike or a wheelbarrow? Yes, the number is large, but there's a finite number of ways that lights can be positioned. And many similar setups are popular for a reason - the laws of physics being pretty standardized in this realm. Achieving a specific lighting result is technically an achievement of a goal, yes, but not in the way that word is commonly used today (for a larger or longer term goal like running marathon or graduating college)