Comcast tripled my bill for internet after one year and was also charging me for occasionally going over their data limit they set after I had been a customer for a couple months. I called Comcast and specified the day I wanted my service to end and had it coincide with the day I scheduled for RCN to connect my internet. The only annoying part was having to tell them more than once that there was no discount that would make me want to stay a customer since they were just going to pull the same crap in another year.
My father passed away a few years back and my mother was trying to cut back on expenses, so she went to cancel the Comcast. The account was in my father's name, so she expected there to be some trouble. Comcast required that she bring in my father's death certificate. Also, they would be keeping the death certificate for their own records and a photocopy wouldn't do, so she'd need to go down to the county corner and get a second copy of the death certificate printed and hand signed. While this all seemed fairly onerous, I can at least appreciate the formality from an security standpoint.
After jumping through all of the hoops set forth by the Comcast, my mother drove out to the local branch office and presented the paperwork. The case worker brought didn't know how to handle the situation where someone had actually done everything that Comcast had asked and brought in the branch manager. He then told my mother that they needed my father to personally deliver his own death certificate before they would close the account.
Also in the past (different cable provider) they had it MAC authorised so I couldn't use my new modem. But then I set the new modem to use the MAC of the old one and it worked. So same
All DSL lines have same L2 interface as ATM and thus there is no authentication. How the authentication works is that PPP gets tunelled through this, either by running PPP directly on AAL5 (PPPoA), or more commonly and somewhat nonsensically by tuneling by wrapping PPP in ethernet frames that are then transfered inside AAL5 channel (PPPoE, or more correctly PPPoEoA). Interestingly this is usually used only on the first virtual channel (ie. the "Internet" one) and not on the additional channels that you typically get today (IPTV, VoIP, free hotspots...), these additional channels are usually straight Ethernet over AAL5 with the modem behaving like simple L2 bridge (often these channels form relatively large broadcast domains that are typically NATed to the Internet).
[Edit:] In contrast, DOCSIS variants for Internet over CaTV are derived directly from IEEE 802 family of technologies and there are no telco-style ATM/X.25/whatever protocols in between. Good first approximation is that the DOCSIS segment handled by one CMTS behaves like one big ethernet switch. But beacuse of the nature of shared medium, data on the coaxial cable is encrypted as otherwise it would be trivial to eavesdrop on anyone else on the same segment. The encryption even involves PKI to mutually authenticate modem and CMTS.
On DSL there is clear physical interface on the network side, that can be turned on or off, shaped and metered which is everything that the ISP cares about from the charging and authentication PoV. CaTV does not have anything like that and thus there has to be relative complex authentication and confidentiality mechanism (that is, somewhat paradoxically, usually completely invisible to the end user).
I worked on workforce management software for utilities companies. The field crews often only see information about their current task for various reasons (data size of standing data, privacy protection, field crew is a contractor).