I've recently begun learning about Cyber Security related to Bluetooth. I toggled the "Show Bluetooth devices without names" (or something similar) in my phone in developer mode and went to the supermarket. I detected tens of previously undetectable Bluetooth MAC addresses. When I looked them up online in sites such as this one I couldn't find a single one, except for the headphone icon.enter image description here My questions are:

  1. Is this normal? What are the most likely devices for these addresses?
  2. I thought that perhaps certain devices such as fridges, might have bluetooth connections. However, wouldn't the vendor be shown in mac finder pages?
  3. When I went to a quieter area of the supermarket, the number of addresses dropped significantly. Would this mean that: A) Everyone (or at least a lot) of supermarket customers are using a mac address changer in their devices, and B) keeping Bluetooth on at all times?
  • "wouldn't the vendor be shown in mac finder pages?" -- that would depend on the database you used. Can you explain your reasoning for the 3rd question? It doesn't make a lot of sense. If you were in a quieter part, then you wouldn't be around so many BT devices. I'm not sure how you are jumping to "MAC changers"
    – schroeder
    Jun 9 at 16:11
  • Apple and Android phone randomise the wifi and BT MAC addresses.
    – schroeder
    Jun 9 at 16:17
  • Thanks for your replies. Reasoning for #3 is that I wanted to check whether it was people's devices or devices in the supermarket. Since I had no idea that Android phones randomize MAC addresses too (my Android phones don't, at least by default, and I don't know whether people would be savvy enough to do it if it's something a bit more involved), I wondered whether these were other types of devices.
    – Basti
    Jun 10 at 14:24