Somewhat disingenuous to suggest swapping sim cards to avoid being tracked. This myth is one that law enforcement love. They just track phones with IMEI numbers.
If you can patch firmware of your phone you can forge IMEI. Most of phones have IMEI in OTP flash, but with unlocked boot loader modification of code which actually send it to network is usually possible.
Many cheap Chinese phones on MTK chipsets produced at non-working time without knowledge of factory owners don't have unique IMEIs, they have all zeroes or all ones in it so user can flash it itself one time; loads of fake iPhones with quadro SIMs and analog TV support can have IMEIs of few real iPhones.
> produced at non-working time without knowledge of factory owners don't have unique IMEIs
I've had odd troubles with USB devices for the same reason; a bunch of them with identical or overlapping serial numbers. I wonder how much of a problem it causes for the operators, I doubt their systems were originally designed to accept duplicate IMEI.
AFAIK the IMEI and IMSI (IMEI for subscribers) are nothing more than client side variables. The telcos have their own internal designations that relate to billing and active connections.
The idea behind "swapping SIMs" to avoid being tracked assumes that the phone itself can't be identified and tracked (regardless of the SIM card in it). Once one of your SIM cards can be identified as belonging to you (maybe you break down and call a relative), it can be linked to the phone. If the phone can be tracked, then all of the other SIM cards that you use with it can be linked together, regardless of the whether or not the original purchase of the phone or SIM cards can be linked to you (cash vs. card).
I think he's referring to the artificial security based on swapping SIMs into the same phone, since both can be tracked. In fact, with appropriate metadata[1], this could poison a number of SIMs and phones if they were ever passed between handsets and/or people.
Now I'm imagining the trouble one could cause with a cell-phone recycling bin at Best Buy.
Well fine there's cloning a phone, setting a bogus or duplicate IMEI, or simply buying cheap throw-away phones. Here, have a look at a really terribly done video of one electronics market in HK. One of many. https://www.youtube.com/watch?v=dxTR5X0PIP4
I don't know about you, but where I live (Western Europe) it would be much harder to come up with an anonymous SIM than an anonymous phone.
I could walk today in any second-hand shop (selling used CDs, videogames, books, coffee machines etc...) and buy a crappy old unlocked Nokia, for less than 20 bucks, cash, no ID required.
But if I would need a SIM card, even if top-up, I would need to go to a service provider and give at least a valid ID.
The weak link would still be the SIM, not the phone. A place where you could easily get anonymous SIMs would be a definite advantage in order to mantain anonymity, so I guess the author has a point.
