Good point.

> but why do all these arguments against backdoors never mention this?

However, I don't think arguments against back doors should mention TSA luggage locks! It's a bad prior.

You don't want people in the "airport" mindset when you're trying to convince them not to allow the government to snoop.

People who enter airports (or especially customs) basically give up all of their rights to privacy. And most Americans are apparently OK with this. Begrudgingly, perhaps, but ultimately most people accept it and go on with their life.

So, "think about airports" is a really terrible persuasive setting.

Instead, you want people thinking about their bedroom. About their car. About their child's playroom. About the settings where they live 99% of their life. Because that's the setting that government back doors in consumer electronics expose. And that's the setting where people get most uncomfortable about carte blanc government access.