I think it's a matter of (a sketchy understanding of ) physics, the denser the material the easer it should be to detect. But going by that logic the com-badge should have been easy to detect. My thoughts, if you go for a 'Skeletal Bone Lock' transport you get every one's bones good guys, bad guys, indifferent guys (and I'm not talking about leaving the other tissue behind) and parts of near-by structure like parts of the ground the people were standing on. making a very big mess for someone to first explain and then clean-up.
Phoenix...
"I'm not saying there should be capital punishment for stupidity,
but maybe we should just remove all the safety lables and let nature take it's course"
"A Place For Everything & Nothing In It's Place"