Do not whistle at night during chinese ghost month

Have your grandparents or great grandparents or your parents told you not to whistle at night during the Chinese month of ghost between july and august which is also when we celebrate the mid-autumn festivals? If nobody told you not to do so then it is better you do not do that at night because it is said it attracts the good brothers or sisters out there. By good brothers and sisters, they meant to say non-living being that one cannot see. In fact it is better not to whistle on any night of the year.