[Building Sakai] Assignments submissions are unsubmitted when switching away from non-electronic

[Brian Baillargeon]

If an assignment's submission type is set as Non-electronic and the 
instructor changes the submission type to anything else, all the 
submissions for that assignment will be updated to have submitted = 
false and the timeSubmitted = null. This can be problematic if there 
were submissions before the assignment was set to non-electronic. I'm 
working on a patch that will remove this functionality, but I figured 
I'd ask first because it seems like a fair amount of work went in 
introducing this behaviour 
(AssignmentAction.change_from_non_electronic(...) seems to be written 
solely for this purpose).

Does anybody know why this behaviour was implemented?

Thanks,
Brian Baillargeon