Last year, Comcast announced that it would begin rolling out a WiFi program that uses customer hardware to throw a wide public net. While it’s free to Comcast’s own Xfinity subscribers, everyone else is expected to pay for it. Needless to say, Comcast doesn’t offer any kind of compensation or credit to end-users who provide this service — even though providing public WiFi inevitably costs the end-user money.

How much money? An engineer at Speedify set out to test that question using a standard Xfinity Business Hotspot setup, consisting of a Cisco DPC3008 cable modem and a BelAir 20E WiFi router. According to Speedify’s testing, the router draws 0.14 amps when idle and 0.22 amps when loaded. By the company’s calculations, this comes out to roughly $23 per year at mid-Atlantic power rates. Comcast, meanwhile, has disputed the test fairness and wants Speedify to retest using different hardware. Speedify has promised to update the blog post when it hears back.

Objectively speaking, $23 isn’t much, even if you’re dirt poor, and the $23 figure assumes that the WiFi router is used 24/7. A more realistic assumption might be $10 to $12. Electrical costs, however, are only the beginning of why we have a problem with this kind of program. First, there’s no indication that Comcast explicitly assigns different IP addresses to temporary network guests versus standard users. This means that you could wind up on the hook for something a guest did while using your hotspot. It’s pitifully easy to spoof the SSIDs of these types of public hotspots — and while that speaks more to security precautions in Android and iOS than a problem with Comcast, the company is still opening users up to increased attacks by pushing ahead with its network plans.

Finally, there’s the fact that, once again, cable companies get to play by different rules than everybody else. It’s perfectly fine for them to charge you rental fees in perpetuity for your cable modem and to increase those fees at will, and to charge you for the privilege of running a WiFi hotspot on which they make money — and then to charge you for the electricity used to run their own for-profit WiFi network. It’s an issue of principle as much as anything, and while Comcast does provide the ability to turn the Xfinity setting off, they’re fully aware that the overwhelming majority of customers lack the expertise to find the setting or disable it themselves.

Speedify isn’t a neutral party in this — the company sells a software product that’s supposedly designed to help Comcast customers recover bandwidth through channel aggregation — but their data shows how telcos are shifting costs to their own customers to prop up profit margins. It may only be $8 to $10 a year, but take that amount times Comcast’s millions of subscribers, and it’s a healthy chunk of cost that the company doesn’t have to pay for.