It's a code of honor, really. Unless you get someone else to do it, it's all I can do. I don't have D2 anymore, and when I did it was Nezmod.
You have my offer. I won't give the points away unless you both agree on how it turned out. That way, if one of you doesn't hold up your end, the other still loses out.
If the armor changes hands, one of two things will happen:
A) He'll lie and say he didn't get the armor while you say he did, and you'll be out your armor, but he'll still have lost his 1000 points. It's obvious you're not USING the armor, so it's no big loss.
B) You'll both agree that the armor went properly, and I'll give you the money.
In the case of him getting the armor, it wouldn't make sense for you to say you didn't give it to him...that would mean I didn't give you the points, and he got it for free.
If the armor DOESN'T go to him, one of two things will happen.
A) You'll both agree that you didn't do the swap, and he gets his money back.
B) You'll lie and say he got it, while he says he didn't. In this case, you don't get the points, and he's just out his 1000, which he can surely make back in a variety of ways.
And if either of you are dishonorable and try to cheat the other, I end up with 1000 points of my own for my troubles. =)
So, the capacity for one person to get screwed is possible, but the other person won't get anything out of it.
EDIT for Johnny: Genesis is worried about him giving the buyer the armor, but the buyer still denying he received it, and therefore getting his points back.. The system I just defined would destroy that possibility.