It's generated a ton of hype and interest. I suspect that's one of the main reasons.
"Are you deemed worthy of a CR-48 by Google?" (This is not an official Google quote I'm just laying out the sentiment)
And the problem with that is...some people won't be. So when you look at using the package arrivals for hype you have to realize you're rubbing it in the nose of everyone who didn't get one (and the ones who did are already happy with you so they're already hyped up).
I suppose there's a third group that wasn't interested enough to even apply but I can't imagine those people being moved by a bunch of "my CR-48 arrived" stories.
Google is trying to start a movement with the Chrome OS. They're trying to win people over to the thinking that you don't need a desktop. So the dynamics here are more like a political party than a giveaway. As such people are bound to get emotionally invested and their feelings of rejection are bound to be amplified if they are rejected from that movement (imagine a political party that only accepted people's support after an application process)
As I said it's a necessary step because this is a testing process and Google does need a certain profile of person to test. But that doesn't mean it isn't going to sting people if they don't get in.
Again it's not the same as other closed Betas. It's a movement towards an entirely different computing model. One that not everyone accepts is valid (in fact I'd argue most don't think a completely browser based computing experience is valid at this point). So what Google needs more than anything is people who are passionate about that idea and who will strongly advocate for it.
So when people are rejected from the program I don't believe they'll cry but I do believe they'll feel less passionate about the idea as a whole.
They are definitely trying to get these out and make sure you get it. I have no connections with Google and I am not a member of the press so to receive this level of service was amazing.