I could not get my statement out of what I was trying to quote earlier, so I'm reposting
There are three reasons I can think of for a closed casket: First, morticians are picky. My brother was killed in an accident that damaged his right eye in a way that the mortician could not cover up, so he only allowed a single viewing by the immediate family, with damaged side covered with a cloth.
Secondly, the news of his gruesome accident (he was pulled into a large round hay baler and crushed) was very sensational in our small farming community, and the mortician said that if the public knew there would be an open casket at the funeral, strangers might attend out of morbid curiosity.
Thirdly, allowing the public see the location of any wounds, even if they weren't disfiguring, would have been revealing evidence in a still unsolved murder case.