As I explained on skyblock when this was first established there.
When you sell in-game items for real money, you are benefiting financially from the server.
If you're giving that money to another server, it's even worse.
The only way these types of trades were legal on skyblock was if the money was for a skyblock upgrade only.
That way, the money returns to the server anyway.

Plus, when I brought this rule up a while back on a thread similar to this, I got shot down and corrected, so thanks for catchin' on guys.
:t: