Ars writes:

Unlike the guest networks that Internet customers set up for visitors, for which the homeowner can choose a password, the Comcast hotspots can be logged into by anyone with a Comcast subscription or anyone who buys temporary Wi-Fi access passes from Comcast. That means random people passing by your home could use the hotspot to get on the Internet.

…

It may be unlikely that a hotspot will be used by passersby constantly, but if it were, it would cost the Comcast subscriber “up to $22.80 per year for those of us here in Philadelphia, or $1.90 per month,” according to Speedify.

It’s not really amount the money, but about the principle of the thing.  Also, as one wise Ars commenter put is:

If Comcast’s network can handle the extra load on it by having 1 million public WiFi hot spots on it — someone remind me why they need to have data caps again?

Just another reason to buy your own equipment rather than using the equipment Comcast and other ISPs rent out to you. When possible, I’m always an advocate for owning your tech – one of the reasons my daily driver is a Nexus 5.  The less control these shameless companies have over our devices, the better.