[MertsA]

The TSA does it as well, not having any valid justification has never stopped security theater before.

https://www.theguardian.com/world/2018/mar/12/tsa-surveillan...

[seanmcdirmid]

TFA: A TSA spokesman, Matt Leas, declined to comment on the lawsuit but said: “TSA does not search the contents of electronic devices.”

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.