Criminals can clone a sim and run up charges on other people's accounts. Pretty rare with GSM. I think it's rare in general these days. It was kind of an issue like 15 years ago but I feel like it's more of a social engineering type of thing to be victimized by that, these days. There was a video recently of a guy sitting in a minivan at a mall parking lot with probably 50 phones dangling from wires scanning for vulnerable phones of people walking by. So it does happen still and it's quite creepy.I suspect what he means by cloning is in the legal sense. Where law enforcement will "clone" a phone so they know who's calling, who's being called, and I presume have the ability to use the "cloned" phone to place calls from that number on a different handset.
At least I believe that's the definition of "cloned" he's looking for.
Of course with that said, I see no reason to answer the question. I might get chased away if I do!