This is the result of Xfinity... not Android or iOS devices. If you connect once to an Xfinitywifi hot spot, your device is automatically added to your Comcast Xfinity account. https://customer.xfinity.com/Secure/WiFiDevices to see your WiFi devices and remove them. Then it will nolonger auto connect. Cheers!
I am obviously having the exact same problem as everyone else, seeing as I am on this page. However, I do not even have an Xfinity account, nor have not had one at all since I've had my android. I have the galaxy S7 and want to throw my phone across the room every time I use it while not on my own wifi network. Just another reason I left Comcast, they try to gain market share by shoving themselves in your face then treat their customers like ****.
I've tried turning off notifications from the android system, doesn't work.
I've tried downloading one of those wifi apps, they won't let me forget xfinity.
Someone please find a real solution.