Why so all-or-nothing? Why not dads on the way out and sons on the way back, or vice versa? Or you and your dad on the way out, him and his dad on the way back?

The way I was raised, the standing rule would be to offer the UG to the dads. No question or hesitation. But more than likely, they would decline it. Two sensibilities: "Elders deserve respect" but "Parents want their kids to live better than themselves."