Earlier quoted context omitted.
Let me try again. Assistant Professor of Physics here (not a grad student). Yes, reflectance of room temperature aluminum at those wavelengths is pretty good (not true for all metals BTW). Yes, this usually makes it hard to distinguish thermal radiation and reflected radiation with metals. What are you trying to say though? That whatever comes off from a metal must always be a reflection coming from somewhere else? >…
What are you trying to say though? In the first image in the linked article, the thermal camera picture has a scale at the bottom. On the scale shown white and red are hottest (66°C) and blue and black are coldest (23°C). The CPU is black (23°C), and the PCB directly adjacent to it is white (66°C). kees99 and klickverbot are saying it's unlikely the CPU is actually 23°C, especially given the author's statement the CP…
The CPU is the heat generator there, and is in contact with metallic regions around 60C (the red ring, if you compare to the real picture and follow the metallic bevels), where heat conductivity abruptly drops, which is what I've been talking about from the beginning. Since the heat is generated by the CPU and flows to the metal casing and to the PCB, the CPU can't be lower than 60C.
I agree that the reading for the inner region of the metal casing (which is not the CPU) must be off, and it's probably because the emission intensity there isn't strong enough and the camera software is mixing the emission and reflection when inferring the temperature (which gives physically incorrect results because the spectrum won't obey Planck's law, but the error depends on how different the temperatures are, and gets much stronger as they drift apart) rather than doing something like a "dark frame" subtraction (which is doable in principle).
Accuracy concerns aside, though, everything we see there (when you consider the physical context) supports the fact that the metal casing helps spreading the heat (which is obvious, it's a material which high heat conductivity, and there wouldn't be any need to put it there otherwise).
Even the 60C reading must be off by some for the same reason (given the regions appearing at around 70C), of course, but I assume OP doesn't care about that level of accuracy.