def check_game_mode(game_mode_name):
    """Validation for a game mode script.

    Check if the game_mode is not a default one ('ctf' or 'tc').

    Args:
        game_mode_name: The game mode name to be checked

    Return:
        bool: True if the game mode is not a default one, False otherwise
    """
    return game_mode_name not in ('ctf', 'tc')
