“…For example, radio‐frequency signals and infrared beams can be used to can detect close contact (1–5 feet) as well as directionality, which can be used to detect face‐to‐face contact between individuals (Olguín et al, ). In contrast, Bluetooth radio waves are relatively far‐ranging but provide relatively coarse spatial resolution (e.g., distinguishing whether participants are 1–2, 3–4 vs. 5–10 feet from one another) (Boonstra, Larsen, Townsend, & Christensen, ; Montanari, Nawaz, Mascolo, & Sailer, ; Osmani, Carreras, Matic, & Saar, ). However, Bluetooth is an omnidirectional signal and thus cannot be used to detect face‐to‐face contact.…”