As shown at the Blackhat 2015 U.S. conference by researchers of Shanghai Jiao Tong University, cloning even a 3G/4G SIM card takes from 10 to 80 minutes, requires a computer, an oscilloscope and a SIM replicator and, of course, access to the original SIM card for the required amount of time. Things get much faster if the original SIM card is a 2G SIM card (issued before 2002).
What happens if a SIM card gets cloned?
“The compulsory registration of ownership of mobile telephones would not deliver any significant new benefits to the investigatory process ..."
In other words, "burners", anonymous "SIM" cards, "SIM" cards under someone else name, all those are as anonymous as our business card!
Yet, a good percentage of questions we receive on Quora keep asking the same question: is it more anonymous if I use a burner or an anonymous SIM card? The answer is always the same. No. Using an anonymous SIM card or a burner does not increase the level of privacy of the user. Have a look at the video in the NEWS section on this page, to understand why.