Internet and security is not that easy in a mobile world. Why? This is much down to technical details and I try to explain this for non telecom experts. For more information and explanation of abbreviations, please scroll to end of article.
In UK and many other countries, you can buy a prepaid card with data allowance, with cash as payment method. I have even done this in Shanghai, China. You don't need to register a name, if needed later, there is nothing that prohibit you to leave false details.
When using a mobile connectivity, the identifiers for the call is the IMSI for the SIM-card, MSISDN for the subscription and IMEI for the phone. This information is part in the CDR from the network when using cell-tower connectivity. There is no MAC-address that could be used for trace-ability.
When using a Wi-Fi network, you can trace the MAC-address, but with an iPhone 6, this address in randomised by session. It's neither possible to collect the IMEI or the MSISDN for the phone when using wi-fi so you can't get this information.
If the phone is paid by cash, then there is no possibility to trace mobile calls to a person, only the that a certain mobile phone made calls from a certain cell tower at a certain time stamp.
The CDR contains information about source and destination addresses, including NAT translation and ports so this is not a problem to capture. But if the mobile device is using VPN-networks or TOR-like services, you are not able to trace what the customer use his connection for.
Finally, you can't control a mobile device in the same manner as set-top box. The customer can use one operators SIM-card an subscriptions in different phones and use SIM-cards from different operators, or no no SIM-card at all in a device bought from an operator.
You can only suspend a customer on SIM-card base for not following the rules, as the prepaid customer can't be trusted. You can not as an operator suspend the customers device, wi-fi connectivity on the device or another operators SIM-card service. It's not possible to remotely change settings on a modern mobile smartphone as an telecom operator.
Unless you become a bad guy that hacks mobile phones.
1) Privacy now and in the future - https://youtu.be/d3WUc4dwTL0
2) Two sides of a coin - http://disruptivearchitecture.info/blog/2015/11/18/two-sides-of-a-coin
3) How to protect yourself when using a free wifi - https://youtu.be/kCZERTjvMeY
MSISDN: Mobile phone number
IMEI: Identifier for mobile devices using cellular connections
MAC-address: Device network address
CDR information about calls, mainly used for Billing