"If you’re a fan of privacy in our age of creeping digital authoritarianism, there’s one famously effective way to pass through U.S. Customs at an airport without worrying about a device search: travel with a burner phone only." What about setting your phone from the get go to store all data on the micro sim card ? Then, when traveling through airports, swap out for another micro sim that has some small, useless data…
I thought the play was to travel with a burner and mail the real phone to a drop somewhere in the destination country. Supposing you could just put all your sensitive data on a microsim or microsd and do the same thing, but this all feels like different colored wrappers on the same piece of candy: don't bring data you want to keep secret to the place where they're allowed to use force to steal secret data. Obv packages are subject to search and seizure at borders the same way you and your phone are but a package in the mail has the advantage of volume and relative anonymity. There are a lot of packages and not enough resources to seize and search all of them, and it's harder to tie the package to a person or entity that warrants increased suspicion if it's mailed anonymously from another country than it is to tie a phone to the guy whose pocket it was in when he tried to cross the border.