You mean like any human rights organizations who send people to authoritarian states ?
You mean like any Foreign Ministry sending a courier out in the world ?
You could learn so much about operational security, if you wanted to, just by reading open sources.
Can I recommend you start with a wonderful old article called "A first tour like no other" ?
If your adversary model is a wild-eyed gun-slinging mid-west racists and you are black, then encryption is not going to be a factor in your death, and speculating what you can or cannot convince them about is besides the point.
If a sane adversary has captured you and your devices, say border police in some police-state like Belarus, Brazil or USA, it would be silly to assume that you know more about disk-encryption than they do.
Most importantly, you would be very silly to assume that they will not simply lock you up, until you provide access to the device, aka "XKCD538-lite".
There are people who have languished in hell-hole jails for years already, not because they are unwilling to provide access, but because they cannot provide access, but are unable make a convincing showing of that.
Competent organizations make sure their travelers can make that showing convincingly, and one of the steps they take, is to make 100% sure there is no unexplained high-entropy data on their devices.
Imagine ending up in a foreign jail for years, just because you once deleted a huge gzip'ed file, and the first sectors subsequently got overwritten ?
Yeah, that happened: "Now decrypt this other secret partition!"