Would using someone else's cellular family plan enhances my privacy?

Questions
1

The big three carriers in the US all offer discounts for having multiple lines. A distant family relative would like me to join his plan so that it’ll bring down the monthly price of his plan. I also get the benefit of a cheaper plan too.

One big benefit is that he has already went through KYC for the postpaid plan. I won’t have to go through KYC to use the SIM. The carrier won’t know that it’s using the data. It also helps that our relationship isn’t apparent because our family names are different. Not that it’ll matter to the carrier after the SIM cards have been issued. Of course, it’s not perfect privacy. Other than getting a cheaper phone plan, do you guys see any privacy gain/benefit from this arrangement?

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2

I’m actually in that situation right now! My phone number is registered under a family member’s plan and I haven’t had to do any KYC checks to get my postpaid SIM. I’d say it’s worth it to me personally.

Benefits so far:

  1. My phone number is listed under my family member’s name in those pesky data broker phonebooks. Any time a telemarketer calls me, they ask if it’s my family member on the line instead of me. My number isn’t linked to me publicly. Maybe your country’s data brokers will be smarter, maybe not.
  2. All my payments go to my family member instead of the carrier. The carrier doesn’t have a direct link to my identity & there isn’t a direct paper trail of me being one of their customers. Can’t have my data leak if it isn’t there in the first place.
  3. The info the carrier sells about us is tagged only under my family member’s name, helping us both obfuscate our profiles from data brokers. My name isn’t in the info at all & my family member’s profile gets flooded with unrelated useless data (my data). Again, maybe your country’s data brokers can figure this out for themselves, maybe not.

Costs so far:

  1. One time my SIM broke. I use a physical one & the one I used was so old that it simply gave out. When I went to the local office of my carrier, they couldn’t provide me with a new SIM card since I wasn’t the owner of the plan, even though I was the de facto holder of that specific number. I had to coordinate with my family member to get a new SIM. This could be different (or the same) for you depending on what kind of a contract structure you’ll have with the carrier.

The limitations:

  1. Law enforcement can still (most likely) figure out who you are since your SIM reveals your location to the network as usual. Even if the plan isn’t tied to your name on paper, your location will still give away your identity to anyone who looks hard enough. You still sleep every night at a specific location & go to work at a certain place during weekdays (if you live like most people do). This may or may not be a problem depending on your threat model.

I’d say that there is privacy to be gained from such an arrangement, if you’re ready to deal with the costs. I’m personally willing since SIM cards breaking or contract changes are quite the rare occurances all things considered.

Whatever you decide to do, good luck on your privacy journey. :hugs:

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The limitation you cited is exactly what I was thinking. I’m really curious what others think about this subject. It’s unfortunate that cellular technology isn’t very private. I agree with everything you said.

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I wouldn’t jump to this conclusion just yet.

For example in 5G any exchanged data contains the SUPI (permanent, unique ID for a SIM-card) but it also contains the PEI (permanent, unique ID for the device). If you swap the SIM in your device, your SUPI changes but your PEI remains the same if you keep the same phone. So regardless of SIM your device is always identifiable, even before looking at “behavioral patterns”.

The value used as PEI for 5G is typically your device’s IMEI, which is the “international mobile equipment identity”. Kinda like a MAC address on your computer. The IMEI is “known” to the operating system (you can check it in your phone’s settings or by dailing *#06#.

This ID is connected to your Apple, Samsung, or Google account which ever you happen to need for your specific device manufacturer. I suspect those accounts aren’t using your relative’s name and email.

So, depends on what you fear and whom you want to be anonymous towards :slight_smile: