It's to tell you how busy the wiring closet is, before you visit
A student in the US found hidden Pis were being used to count MAC addresses to generate busyness heat maps for college facilities. See https://youtu.be/UeAKTjx_eKA
A student in the US found hidden Pis were being used to count MAC addresses to generate busyness heat maps for college facilities. See https://youtu.be/UeAKTjx_eKA