Earlier quoted context omitted.
Yeah, someone would have to leave a Raspberry Pi zero sized chunk of explosive out to put up a boot screen and something close enough to a windows boot logo to pass a cursory visual inspection. In reality, the X-Ray should already make it pretty clear if there is something weird about the laptop's build. Turning on the machine is entirely unnecessary. Also, I have not been asked to turn on a laptop in many years, so…
The metal casing of many laptops reflects the xrays, hence you can't see anything inside them.
In my experience there is always a detailed image of the inside of laptops. Color-coded according to material type/density and clearly showing the location of batteries, etc.