Double-space (or more) after command alias is no longer accepted, i.e. "f home". Otherwise, command prevention routines (in Factions itself and in other plugins) can be bypassed. For example, preventing the "f home" command wouldn't prevent anyone from using "f home" or "f home" instead.

src/com/massivecraft/factions/zcore/MPlugin.java

@@ -199,6 +199,9 @@ public abstract class MPlugin extends JavaPlugin
 			
 			for (String alias : command.aliases)
 			{
+				// disallow double-space after alias, so specific commands can be prevented (preventing "f home" won't prevent "f  home")
+				if (commandString.startsWith(alias+"  ")) return false;
+
 				if (commandString.startsWith(alias+" ") || commandString.equals(alias))
 				{
 					List<String> args = new ArrayList<String>(Arrays.asList(commandString.split("\\s+")));