I'm curious. If you were to create a file and place it on a network drive instead of the user's C: drive, would the file creation date and time be that of the user's computer or the server in which the file resides? If the latter, perhaps instead of a time stamp, you could create/edit & save a small ASCII text file and then note the time of creation/last save. IF the time is that of the network server and not the local computer, that is something users cannot mess with.
Michigan Dept. of Environmental Quality, Air Quality Division