As a follow up to why you need to restart your boxes after this patch, load up process explorer and search on how netapi32.dll is used in a running system:
Could one shut down the computer browser service and the server service and restart them after the patch is installed and be protected? Look at that list of running services. That’s an SBS 2003 box. One of those is Exchange.
Dr. J has always said that you could use process explorer to determine where all those dll’s were running, shut them off, patch and manually restart them and then you’d not need to reboot, but look at that list on your boxes as well. Are you certain you will be able to manually shut down all of those processes?
Bottom line, we need to reboot. It’s the only way to be certain that all of those dll’s are flushed out of memory and not still in use.