Well,
you can (or not) show the rows dynamically.
Enter in the subquestion relevance of
person 2 "!is_empty(Q1_SQ001)"
person 3 "!is_empty(Q1_SQ002)"
So only one empty row is displayed if the row before was filled.
The same in question "trips"
Show only rows where are data in Q1.
person 1 "!is_empty(Q1_SQ001)"
person 2 "!is_empty(Q1_SQ002)"
The oldest version I can test in is 2.06. I am not sure if the subquestion relevance is available in 2.05.
See:
Joffm
BTW:
Please overlook the layout of the trips question.
Who is able to read this?
Better to have the explanation separately. And the repeated "number of ... in a typical week" also should be separated as a general hint.