How can I programmatically prevent the PC connecte

Question

As noted here, I added code to my handheld app to (attempt to) prevent certain types of files (by extension) from being synced to the PC. But this doesn't work if the user, on the PC, uses ActiveStync to enable file sharing. On doing so, regardless of handheld registry settings, it copies files from the handheld to the PC (from the handheld's \My Documents folder to the PC's C:\Users\clay\Documents\Documents on Clay's Device folder).

Is there a way to programmatically prevent (on the handheld/Windows CE side) this syncing from taking place? Or is it just a matter of the user reaping what they sow when they select file syncronization?

UPDATE

See this (I'm not completely preventing syncing, but I'm preventing the syncing of the files that I don't want to have synced, by making sure that the FileSyncPath registry key does not match where I am saving the data in question).