since nobody trusts them.

Which is entirely understandable. :P

They do.

I know my last Pre-Order (Life is Strange) from Humble didn't give a key until the actual launch date, and that's my only digital-purchase pre-order experience within the past decade or so that I have to work with (with my other pre-purchase experiences being storefront- or backer-based). :P

Likewise, Humble's FAQ on the matter only states "When you buy a Pre-Order, you will receive a blank download page that is awaiting content.", so I assumed their approach was consistent in that regard. Further, I've the understanding that the first Pillars didn't give a key until launch on Humble, since there were comments to that effect [including an official reply from Humble stating the keys wouldn't be available until launch, when the first game's early-release backer keys were brought up with them].

You no doubt have far, far, far more experience with Pre-Orders than I do, given my single non-backer, non-storefront dip into such waters- but from what I knew of Humble and the first Pillars, I figured that a confusion over game version was a probable enough conclusion to come to. I'm of course not stating that such any expectations in that regard, I'm just noting that it didn't seem a stretch to consider that as a potential explanation (given the first game's recent bundling, especially).

If Humble and Obsidian aren't as consistent on their approach as I thought, then yeah, it's a lot more up in the air (though, again, my earlier comment was just meant as an idle discussion of possibility, and in no way was meant to firmly imply anything about the giveaway to begin with). :)