If you have Comcast and you are using their WiFi service, then they are almost certainly using your router to broadcast a public access WiFi connection. What’s more, they are making it very difficult to disable that public WiFi connection or to opt-out.
Comcast has a somewhat noble goal of providing WiFi connectivity to subscribers across its entire footprint. As a Comcast subscriber, this is very convenient, of course. Initially, this was an opt-in service that Comcast offered to its subscribers who are using the Comcast WiFi router. Now, however, the “xfinitywifi” public access is being turned on by default on all of these routers. This may not bother most subscribers, but there are some business customers who are not enthusiastic about sharing their bandwidth with a public access. Although it is difficult to disable this access or opt-out, it is only an issue if you are using Comcast’s WiFi enabled routers. You can choose to purchase your own WiFi router and request a modem without WiFi capability. Many businesses may want to opt for this setup, especially if they are located in a fairly public area where many subscribers may be using your bandwidth.