"Too easy for dogtags (even redundant sets) to get blown away and DNA is like chipping every cubic mililiter of the body."
Ever see Hamburger Hill?
Really the lesser of the three Vietnam War movies that came out in the 1980s, but good in its own way...
(liberal paraphrasing)
"He's got no *expletive deleted*ing head! How the *expletive deleted*ck am I supposed to identify him without a *expletive deleted*ing head? You tell your people, one dogtag around the neck, one dogtag in the boot!"