Outlook closed
What happens if the PA enters an appointment to the public folder, but my Outlook is closed?
As long as your Outlook is closed OLMixedFolders can't do it's work. So you don't get that appointment to your phone!
If you need an application which is acting also if you are not every day in the office, please take a look to ExMixedFolders which will do that in the background for you.