I lived in a multi-unit apartment building and one day noticed my internet was down (I was a Comcast subscriber). I was suspicious because a Comcast technician was just out earlier in the day installing internet for a new tenant in the building. After going through the phone support steps they scheduled a technician to come out and check the line.
A couple days later, when the technician arrives, he checks the line only to confirm no signal. Then he goes out back to the cable box outside. I was unable to check this myself since it was mounted high on the building and required a ladder to access. Within a few minutes it was working again.
The Comcast technician then told me my line was just disconnected. I asked him if the previous technician made a mistake during the install. He said something along the lines of: "No, often in these multi-unit buildings we will disconnect people at random in case they are trying to steal cable. If they are a paying customer they will call and get it turned back on". He then went on about how they would have fun disconnecting competitors, and that competitors did it back to them etc.. all very nonchalantly and candidly.
I then called Comcast and got a 3 day credit for the outage they created "intentionally" to prove I am a customer.