I’ve made the effort to secure mine and am aware of how the trusted protection module works with keys, Fedora’s Anaconda system, the shim, etc. I’ve seen where some here have mentioned they do not care or enable secure boot. Out of open minded curiosity for questioning my biases, I would like to know if there is anything I’ve overlooked or never heard of. Are you hashing and reflashing with a CH341/Rπ/etc, or is there some other strategy like super serious network isolation?
They could open up the laptop to insert a small device that reads the usb header. Or just replace the guts of the laptop with something else. Or replace one of the usb leads in your bag with one with a tracker. Or sell a usb-c cable with a tracker for cheap in the gift shop.
There’s a bunch of other ways to compromise your system and some might be easier than putting a backdoored bootloader on your device.
Also, if it’s the TSA, they could almost certainly create a bootloader that was signed by Microsoft to replace any existing one.