Only press button once.

src/engine/net/client/handlers/SwearInGuildHandler.java

@@ -66,11 +66,17 @@ public class SwearInGuildHandler extends AbstractClientMsgHandler {
                 ErrorPopupMsg.sendErrorMsg(player, "Your guild is not a nation!");
                 return true;
             }
+
             if (!nation.getSubGuildList().contains(protectorate)) {
                 ErrorPopupMsg.sendErrorMsg(player, "Your do not have such authority!");
                 return true;
             }
 
+            if (protectorate.guildState.equals(GuildState.Petitioner) == false) {
+                ErrorPopupMsg.sendErrorMsg(player, "This guild has already sword fealty!");
+                return true;
+            }
+
             if (!Guild.canSwearIn(protectorate)) {
                 ErrorPopupMsg.sendErrorMsg(player, protectorate.guildState.name() + "cannot be sworn in");
                 return true;