I want to know if you can kill some one after giving them a fair warning that if they come close they will die, is it fair for the person to file a ban complaint on you and why? Another thing is if that person dies after that warning you take their stuff that they dropped and don't give it back is that considered greifing? Last if you give them the warning but they kill you and take your dropped items and sit in your house waiting for you is that considered greifing, and is it worthy enough to be a ban complaint? ?

Killing and taking items from "corpse" is allowed.

Stealing from chests and breaking someone else structures is not.

however it is frowned upon