Use DefaultCash for the default cash.

OpenRA.Game/Traits/Player/PlayerResources.cs

@@ -16,9 +16,15 @@ namespace OpenRA.Traits
 {
 	public class PlayerResourcesInfo : ITraitInfo
 	{
+		[Desc("Starting cash options that are available in the lobby options.")]
 		public readonly int[] SelectableCash = { 2500, 5000, 10000, 20000 };
+
+		[Desc("Default starting cash option: should be one of the SelectableCash options.")]
 		public readonly int DefaultCash = 5000;
 
+		[Desc("Force the DefaultCash option by disabling changes in the lobby.")]
+		public readonly bool DefaultCashLocked = false;
+
 		public object Create(ActorInitializer init) { return new PlayerResources(init.Self, this); }
 	}