Is a one SCU box big enough for a player to hide in?

I mean, if you fold them.

What if you're crouching? Could you ship a player in a cargo container?

Yeah, I think so. It may not be comfortable.

Talking about the future of cargo, 1s, 2s, 8s, 16s, 24s and 32s are the current SCU boxes that we're looking to support. 32 being something that a semi would pull, the classic shipping container size. That will fit nicely in the back of a Freelancer and things like that. There will be larger boxes that you would be storing more commodities in. But they'll all be symmetric.

So yeah, just to speak more directly: if you crouched and tried to get in one, it probably wouldn't quite fit. But if you killed someone and they were ragdolled, you could probably get them in there. But you can't open the boxes anyway. It's all theorycraft.