One is unavoidable if you want to fly, the other is security theatre. It's reasonable to complain about policies which are ineffective even if the harm is small relative to other sources of radiation.
It's reasonable to complain about security theatre from the standpoint that it is security theatre. It is not reasonable to complain about a policy for from the standpoint that it causes physical harm if the level of "harm" inflicted is orders of magnitude smaller than other aspects of the same activity.
This is not a what-about-ism, because the very act of flying (which is what border security policies are strictly related to) causes "more harm" in this specific context than the policy itself.
The harm caused by flying itself is also incredibly insignificant, but if someone is going to argue that scanner's radiation is the reason people are getting sick then they must agree that the radiation from the act of flying itself is a much larger issue (and discussing scanner radiation would make no significant difference to whatever harm they think the radiation is doing).
~0.9 μSv concentrated in on the surface of the skin is a much higher cancer risk than that same radiation spread over the body. A traveler that goes through these things 200 times a year for short flights really does have a significant increased risk of cancer. Even if they are slightly under the 250 μSv full body dose limits at 180 μSv due to that concented exposure.
> A traveler that goes through these things 200 times a year for short flights really does have a significant increased risk of cancer.
You are describing someone who travels on a plane four days a week, every week, and never takes vacation days. This person also must be checked using the full-body scanner on every single one of their trips (because the magnetic walk-through arches don't use x-rays and thus doesn't have any radiation to speak of -- they use magnets). I think it is more than fair to say that your example is ludicrously cherry-picked -- even if enough people traveled that often to be important enough to bring up in this discussion (the only example I can think of is airplane staff and crew) they almost certainly would not go through a full-body scanner every time they fly.
There was also a study in 2013[1] (which tested the actual scanners in LAX rather than some mocked up scanners), and it claims that a full-body scan only imparts ~11 nSv -- which is almost two orders of magnitude smaller than your ~0.9 μSv figure. I'm not sure which is correct, but I do have a source for my figure.
> Again though it's not a question of full body does as this is highly concentrated radiation exposure onto high risk tissues.
I think you're missing my point on full-body scanners. As far as I'm aware (at least whenever I've traveled internationally), only a small number of passengers any given day will go through a full-body scanner. Most passengers just go through a regular magnetic scanner which doesn't have any radiation (and for domestic flights in Australia there isn't even the option of a full-body scanner). The point being that even if someone travels four times a week (200 times a year) they still won't go through a full-body scanner (and thus won't be exposed to the radiation from such a scanner) anywhere close to 200 times a year.
This is dependent on airport and timing. As initially developed in the US everyone at some airports where going through those scanners. But, various policies and types of scanners have been developed.
Under the current system few people are going to get cancer. But, in the past people where calling systems that where dangerous safe.
I'm sure people get rejected from precheck. I doubt that people rejected from precheck would take up a job where they have to travel on a plane four times a week on average (or rather, they travel enough that they go through a full-body scanner four times a week).
This is not a what-about-ism, because the very act of flying (which is what border security policies are strictly related to) causes "more harm" in this specific context than the policy itself.
The harm caused by flying itself is also incredibly insignificant, but if someone is going to argue that scanner's radiation is the reason people are getting sick then they must agree that the radiation from the act of flying itself is a much larger issue (and discussing scanner radiation would make no significant difference to whatever harm they think the radiation is doing).