I'm trying this on my phone right now for you.
Here is how I tested:
Edit photo from "camera roll" collection in LR mobile with extreme changes.
That photo synched to LR desktop ok with extreme changes intact.
Go to "camera roll" (not LR mobile), delete the example photo.
Check that LR mobile synch is complete
example photo is still in LR mobile camera roll collection and on LR desktop.
On LR desktop, right click on example photo in From iPhone Photos collection, click on show in Explorer (assume Finder on MAC)
Original unprocessed example photo (as viewed in Explorer) is present.
It looks to me like the LR mobile synch process transfers photos out of the camera roll on the phone to a folder on your desktop hard drive that are not removed when you delete from camera roll.
Hope that helps
Thats awesome - thanks Ken.
What do you think would happen with me not being able to sync with LR desktop until next week? If I delete my camera roll pics would that be ok?
Not unless the photos have been previously synched. See above reply ref the transfer of your camera roll as part of the synch function. I would not delete any photos from the camera roll that have not been synched with LR mobile to the LR desktop.