Do You Trust Factory Focus?

Adding to that, how do manufacturers know if the camera is properly focused? Do they have a technician actually verify each camera? How do they verify it?

Also, what's the risk and frequency of it being shifted in shipping?

I think it's all well and good to say you SHOULD always check focus when you're installing a camera, but there are two factors here:

1. The manufacturer is claiming that this camera is a fixed lens focused at the factory. When they ship a camera with a lockring installed that doesn't allow you to turn the lens easily, and you have to remove three screws you're likely not supposed to remove just to loosen it and focus the camera, I hardly think it's reasonable to expect installers to refocus every time.
2. Fine focus on multi-megapixel cameras is getting much more difficult to determine. A lot of 1080p and higher fixed domes are (at least I believe) shipping without true megapixel lenses. ACTi, for example, sent out an email blast with a 10MP fixed dome on sale for $200. Even if the camera is perfectly in focus, that camera is not using a 10MP lens, and poor light handling or softness/sharpness settings can make the image look out of focus even if it's not. So how do you guess in the field which issue is causing it?

So it's not just as simple as saying you should refocus in the field and that's that.