Even using video not everybody not wearing a tag must necessarily be an enemy.
RFID tags have a very limited range and should be used in a canalized entry path (for good reception) within sensitive areas including video surveillance.
It's common practice to mark sensitive areas with warnings to shoot trespassers without prior warning.
RFIDs can assist by identifying "friends", but the final decision about potential enemies has to be met by guards.
RFIDs can't be used to "broadcast" video.
Boncuk