gistfile1.diff

--- a/src/com/martinbrook/tesseractuhc/listeners/SpectateListener.java
+++ b/src/com/martinbrook/tesseractuhc/listeners/SpectateListener.java
@@ -25,6 +25,8 @@ import org.bukkit.inventory.DoubleChestInventory;
 import org.bukkit.inventory.Inventory;
 import org.bukkit.inventory.InventoryHolder;
 import org.bukkit.inventory.ItemStack;
+import org.bukkit.block.Chest;
+import org.bukkit.block.DoubleChest;

 import com.martinbrook.tesseractuhc.MatchPhase;
 import com.martinbrook.tesseractuhc.UhcMatch;
@@ -128,6 +130,8 @@ public class SpectateListener implements Listener {

                                 InventoryHolder invh = (InventoryHolder) e.getClickedBlock().getState();
                                 Inventory inv = invh.getInventory();
+                                e.setCancelled(true);
+                                if (! (invh instanceof DoubleChest || invh instanceof Chest)) return;

                                 ItemStack[] contents = inv.getContents();
                                 for (int i = 0; i < contents.length; ++i)