"an F2F interaction was recorded when three conditions were met: two or more badges (i) were facing each other (with uninterrupted infrared line-of-sight), (ii) detected alternating speaking, and (iii) were within 10 m of each other."

I wonder if condition (i) makes sense. From my experience in open offices, communication mostly happens when I and some colleague are both sitting behind our pc's. So there is no uninterrupted line of sight.