Even if it does have a wifi radio, if you bought your own from someone other than Comcast, you probably aren't part of the Xfinity hotspot system.

Did you know that cable modems -- whether you rent 'em from Comcast or buy 'em yourself -- download their configuration files from the ISP when they boot up?

> ... you probably aren't part of the Xfinity hotspot system.

Because of the above, I wouldn't be so sure (mostly due to Comcast's reputation).

Personally, when I was forced to use Comcast for a while, I purchased my own "dumb" (i.e., non-WiFi) cable modem. I didn't want to pay their rental fees, I didn't want to run an open hotspot for them, and I already had my own -- much better -- WiFi gear.

No consumer bought cable modem/router/AP combo is going to create its own WiFi hotspot on behalf of Comcast due to a config file. Unless it’s the one Comcast provides.

You can turn off the Xfinity hotspots on the Cisco-brand modems. It appears to be neighbors and/or pole-mounted APs that provide the SSIDs where I was.