Top level commands are case insensitive. Thus sub commands should be as well.

src/com/massivecraft/mcore/cmd/MCommand.java

@@ -227,7 +227,9 @@ public class MCommand
 		{
 			for (MCommand subCommand: this.getSubCommands())
 			{
-				if (subCommand.getAliases().contains(args.get(0)))
+				for (String alias : subCommand.getAliases())
+				{
+					if (args.get(0).equalsIgnoreCase(alias))
 					{
 						args.remove(0);
 						commandChain.add(this);
@@ -236,6 +238,7 @@ public class MCommand
 					}
 				}
 			}
+		}
 		
 		if ( ! validCall(this.sender, this.getArgs())) return;