I guess that's the perspective I'm missing.

From where I sit, it's almost unimaginable that those three points are anything but a given. But I've never worked outside of small businesses/startups.

If I don't tell my boss -- the founder -- up front that we can't make a deadline, or that a feature won't happen, it's much more of a risk.

How can programmers help change large corporate culture so that playing politics isn't as important? Or, at least, so that more honest communication can take place without risking blowback?

The dynamics of risk change with the size of the entity involved. For example, in a small startup, losing a hard drive could mean the end of months of work - could kill the company. Or since everyone makes backups / uses hosted services these days ( right? ;) ), maybe a better analogy would be an employee being lost to sickness for months.

In a 100+ person company a broken hard drive should never be anything more than annoying, losing an employee is going to be unfortunate and might even significantly delay a product/feature; but it won't be the end of the business.

There's a raft of interpersonal dynamics which change too; the larger the company the less likely you are to be pally with everyone. Simple factor of surface area - you can't cover them all. So relationships become more formal. As spheres of responsibility begin to form, people develop moats around those responsibilities for better "separation of concerns".

At some point I suppose stuff starts to slip between those self-defined spheres, especially as people move in and out of roles, subtly redefining them each time. Making sure you're not being negligent (or seen to be negligent) in a multi-million dollar company is kind of a big deal if you expect to work somewhere else in future (and especially if you intend to keep working at that company).

While your points are well taken, I'm not sure how those three points change between small & large companies. I'm going to focus on "WARN": the other two seem to be less contentious.

Working in small companies, if I'm not going to be able to make my deadline, the proverbial buck stops at me -- so I'd better own up to it, and tell my boss why it happened, and more importantly, what I'm doing to fix it.

Is it just that in a large company I can spread blame around a bit more? "It's not really my fault -- my team lead wasn't on the ball, we had too much pushback from sales, and if we could cut some of the dead weight from this team..."

Is that the issue? Or is it something I don't see?

One of the most important goals for my "parent" company after we were acquired was to make sure that I (as the first and only employee) was not going to be killing the company if I left to pursue something else or got sick, etc.

So you've effectively got it, it's just that, in a big company, unless you're the CTO or in some other relatively lofty position, the buck probably does not stop with you.

Depends on the company obviously, YMMV, but I think the important takeaway is that "big" companies aren't just larger "small" companies - they're very different entities.

There's an interesting talk from Geoffrey West that (if I recall correctly) is somewhat related to this topic (the scaling of cities vs companies) - http://edge.org/conversation/geoffrey-west

Apologies if I've left you more puzzled than before!

I don't think it makes you look weak at all — putting the success of the team first shows leadership and maturity. Waiting for a situation that covers your ass but hurts the project is not likely to bode well for one's career.