I think everybody should feel atleast a little bit remorseful when they lure somebody, otherwise you are just a cold, heartless bastard.
No matter what your stance on luring is, at the end of the day the result is essentially always the same; you scam/trick somebody out of their hard earned cash, usually taking advantage of their naivety, their good nature, and their willingness to help others.
I have never been lured before, but I can only imagine the feeling of just trying to be a genuinely helpful, good natured Runescape player (the type of players that are in short supply these days, by the way), and instead you get tricked and scammed out of your bank by the very person/people that you were trying to help. It would be a horrible feeling, regardless of the fact Runescape is "just a game."
Would you backstab somebody like that in real life? Would you set them up and betray them, for some miniscule personal gain? The chances are that you probably wouldn't, so no matter if Runescape is just a game or not, you are still harming another human being by taking advantage of them in the worst way possible.
Incase anybody is wondering - yes, I have in fact lured myself a few times. Not the kind of lure where I merely trick somebody in the wilderness to follow me into multi or something like that, but the kind of lure where I befriended the person, gaining their trust and then tricking them in order to gain some wealth. Each person was absolutely devestated, and I did feel horrible.