I guess one way to think about it is to think about whether the Intro diver is trained to cope with the problems that might occur if you run line into a side tunnel. If you disappear, can that diver make the right navigational decision to get home? If the line breaks, or the side tunnel silts out, is that Intro diver ready to cope with something more complicated than simply acquiring the main line and following it out?
When I was GUE Cave 1 (which is one T, no jumps) we discovered we could run a primary reel to a lot of jump lines that come off early in some of the caves. This wasn't completely disapproved -- but when we got to running a primary reel along the main line, and then along the jump line, and then to a SECONDARY jump, we got our hands firmly slapped. They really did not want us in secondary tunnels -- in part because of navigational issues, in part because secondary tunnels tend to have more restrictions and smaller passage, and more silt, and in part because they didn't want novice cave divers kicking the stuffing out of delicate formations.