Originally Posted by
bookworm
However, if instructed to line up behind a departing aircraft, that aircraft may be upwind or downwind of the intersection, thus I may have to wait for an aircraft to pass, or I may not. That requires substantially more situational awareness on my part.
Whether you get a conditional clearance or not will tell you where the aircraft is - so no need for more situational awareness on your part.
If the aircraft is downwind of you (not passed you yet) then the clearance would be given as you had experienced it. However, if the aircraft was upwind (either passed you or was linining up ahead of you) then no conditional clearance would have been given - it would have been either a straight "Line up and wait" if number 1 had rolled passed your position or, if it was still sat on the runway awaiting departure then "Line up and wait, number 2 for departure, number 1 is a xxx departing ahead of you from......."