I'll often punch a manual split in the gps track if I come across a new trail that needs to get added while I'm out running. Mostly as a reminder to go back out with the tablet later and add it in properly.
Yeah, as I was doing it, I was thinking that a split probably made more sense. But in theory the plus sign would also give me info about the angle of the intersecting trail. And I worried that if I didn't get to it for a while, that I'd forget what the splits signified.