I just tried to buy a ticket from CHS to GIG by using Delta from CHS to JFK and RG from JFK to GIG. You can get electronic tickets if you buy the DL and RG tickets by themselves but if you try to link them together (and it gives you a better price), you are required to have a paper ticket even though both airlines have agreements with each other. I agree that the vast majority of reservations can and should be done using the electronic method but there are times where it can't be done.