The TSA already requires that laptops and phones must be powered-on on demand to "prove that they're real". That's already a cybersecurity risk.
I'm relieved that the banned laptops doesn't include my 15" mid-2014 MacBook Pro, or my dad's hand-me-down 13" mid-2015 MacBook Pro that he generously gave to me last week after I helped him repair it.
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 Also, I have not been asked to turn on a laptop in many years, so unless this is a new development it is badly out of date.
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.
The machines are tuned to highlight specific risky materials (such as liquids & gels).
At one point it was common to be asked to turn on laptops etc. But I haven’t seen them do that for years - presumably because the scanners have improved.
Never had any issues with that laptop anywhere else - but they got pretty grumpy at me, and made me power it up to prove that it was a legit laptop.
Flying is not a constitutionally protected activity... see, for example, the legality of un-appealable no-fly lists.
So my guess is that they aren’t supposed to do this, and if a judge ever got the case, the TSA would be in lots of trouble if found doing it.