In the past it's always been possible to save a copy of updates downloaded via Mac OS X's Software Update application.
Recently, however, certain Final Cut Studio updates will only install via the Software Update mechanism. You can download the updater, but it won't install. For instance, the version 5.1.4 update will download several packages to my hard drive.
And I can launch the Final Cut package installer, and it will open in the Installer application. But the splash screen gives me my first hint that something is not right.
I can even navigate to the "Select Destination" screen of the installer, but here I am told that this update can only be installed via Software Update.
To add insult to injury, even though I've already downloaded the installers, Software Update, once quit, needs to download them all over again. Lame. Painful. Awful. Installing this 39 MB update on my 25+ Macs will kill my network. Guaranteed.
The ability to download software updates for later install — or reinstall — is a really wonderful function of Mac's Software Update mechanism, particularly from a systems standpoint. It's sad and more than a little scary to see it not working on certain, specific pieces of software. Here's hoping this trend does not continue.