Add config option

src/main/java/emu/grasscutter/Config.java

@@ -53,5 +53,6 @@ public final class Config {
 		public int MaxEntityLimit = 1000; // Max entity limit per world. // TODO: Enforce later.
 		public int[] WelcomeEmotes = {2007, 1002, 4010};
 		public String WelcomeMotd = "Welcome to Grasscutter emu";
+		public boolean AutomaticallyCreateAccounts = false;
 	}
 }

src/main/java/emu/grasscutter/server/dispatch/DispatchServer.java

@@ -226,15 +226,23 @@ public final class DispatchServer {
 			Account account = DatabaseHelper.getAccountByName(requestData.account);
 			
 			// Check if account exists, else create a new one.
-			if (account == null) {
-				account = DatabaseHelper.createAccountWithId(requestData.account, 0);
+			if (account == null && Grasscutter.getConfig().ServerOptions.AutomaticallyCreateAccounts) {
 				// This account has been created AUTOMATICALLY. There will be no permissions added.
-			}
+				account = DatabaseHelper.createAccountWithId(requestData.account, 0);
 				
 				responseData.message = "OK";
 				responseData.data.account.uid = account.getId();
 				responseData.data.account.token = account.generateSessionKey();
 				responseData.data.account.email = account.getEmail();
+			} else if (!Grasscutter.getConfig().ServerOptions.AutomaticallyCreateAccounts) {
+				responseData.retcode = -201;
+				responseData.message = "Username not found.";
+			} else {
+				responseData.message = "OK";
+				responseData.data.account.uid = account.getId();
+				responseData.data.account.token = account.generateSessionKey();
+				responseData.data.account.email = account.getEmail();
+			}
 			
 			// Create a response
 			String response = getGsonFactory().toJson(responseData);