ISPs smuggling public WiFi into customer's homes?

At one point in time, I had a "business" cable Internet connection, and they shipped me a cable modem, without my permission, and were getting insistent on getting it installed. I balked, because I picked my cable modem for damn good reasons and didn't want a power hog, noisy ass POS clogging my server closet. Part of this is that I separate modem and wifi so I can load things like OpenWRT and have control over my network setup. I don't need another gorram wifi access point.

This got me to thinking though: what if they are using customer's homes as public wifi access points? I found this: https://www.theregister.com/Print/2014/12/10/disgruntled_customers_lob_sueball_at_comcast_over_public_wifi/ - does anyone know if it's a common practice?

I ask because I'm looking at switching to another provider (because it's cheaper), and they are talking of shipping me equipment "free of charge."

Does anyone know any more about this practice?