Reminds me of the Xfinity "Your personalized WiFi summary" emails. Despite returning their router, using a third party almost-layer-2 modem, my own openwrt router (with its own wifi, thank you very much), their emails seem spooky.

They have a counter of all of my devices, somehow (i mean... i guess their count is wrong, but it's infuriating that they try to keep track).