Early Pulling - Is it wrong?

[Kerii]

-snip-

If they are doing it intentionally, and you can prove that they are only doing it to prevent others from participating, you may report them. However, the problem (as I mentioned many posts back) is that you have to be able to prove that they are doing it intentionally. Also, what you describe at first is "Disruption", the person you refer sounds like a griefer. Griefers tend to take advantage of broken mechanics in games in order to outright torture other players. Because it is considered a type of cheating and disruption they're probably more likely to get banned. You'll still have to prove it though.