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],

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. [1] Yeah, I know.