Arguing by analogy is cute but it ordinarily leads to conclusions that are not logically sound and valid products of reasoning. So I'm not going to even address that car servicing matter as it's a different scenario entirely.

That specific harm from the blacklisting is unknown to you prior to boarding/check-in attempt, if any, doesn't make the harm vague and non-existent. Need an example? Whether you accept the following example or not, not my issue: the aviation blacklisting leading to denial of membership in government programs or vocational educational programs despite having incurred application related costs. That is but one of many concrete examples of people having been injured due to aviation blacklisting that was prior to or independent of check-in/boarding attempts. If you want more details about such concrete examples, I'm not here to spoon-feed on demand. Eventually, depending on how long you are around, you may have a chance to see this evidence too -- for government "secrets" are not all secrets for eternity.

It's a travesty of justice that the government mostly gets away with harming, -- secretly or otherwise -- individuals by way of extrajudicial blacklisting and invokes "security" and/or "secrecy" "needs" as an excuse to get away with the harm perpetrated.

Is it really a surprise that lists like the following (from some nutwing paranoid about the paranoid government) become news? If government transparency was far greater and trust levels were higher, that kind of weird behavior would be less likely. Is it really any surprise that former TSA head Pistole's name showed up there? I just hope it wasn't meant to be a Charles II type of blacklist.