Is it standard practice not to disclose to anyone that someone was fired at all? Is it standard to fire your main community manager and not replace her, to just

Is it standard practice not to disclose to anyone that someone was fired at all? Is it standard to fire your main community manager and not replace her, to just stop replying to the community's emails? Is it standard to not cancel a terminated employees appointments? Is it standard to let your celebrity guests fly halfway across the country, wait an hour for their scheduled appointment, and only reveal what happened when their agent calls to complain?