Question about apple updates with images

Hi guys, I was thinking, is it possible to automate the checking & downloading of apple software updates for a particular image? The reason i ask is that I had an idea to just chroot softwareupdate into the mounted image to check for any updates to that image, but it doesn't seem to work. There are scripts floating around on the net that do exactly the same thing - chroot softwareupdate.. and the comments in the scripts seem to indicate that it did work at one point (maybe 10.3 era?). Any ideas?