If I were concerned about this threat vector I would put my SIM in a cheap throw away phone that has nothing installed on it and nothing of interest. I would back up my real phone to several devices and then FedEx (or equiv.) my phone to my destination if I planned to be there a while. I often used FedEx to ship things to data-center locations if I was going to be there for some time. I wore shorts and a t-shirt going through security.