Found this interesting...The US Army places flags at every service members grave at Arlington National Cemetery prior to Memorial Day. As they don't have time to verify every grave it appears they put a flag at every headstone and in this picture it shows a flag in front of Agnes grave which says she is the wife of RDM3 Francis Hilki? and wasn't actually in the service at all.
Just as the others, it is better to put a flag in front of some that may not rate the flag then it would be to miss someone or take the time to figure out every single grave (they place flags in front of 260,000 gravestones on Memorial Day in Arlington National Cemetery alone).
It also looks better when the public is coming to pay their respects.
http://www.arlingtoncemetery.mil/eve...s/FlagsIn.aspx