These days, it's easier to thwart the Evil Maid attack, as it's known, by replacing the device, and some recommend doing that when entering/exiting China, attending DefCon, and a few other scenarios where it's credible under a given threat model. Most of us aren't Edward Snowden, but are still cases where thats not so ludicrous. The FBI has installed keyloggers into laptops supposedly fresh from the factory that have been discovered before. It's not just specific person devices, either. Aspersions were cast on Supermicro motherboards installed into Cloud provider data centers, even if nothing was ever found/proven.