Originally Posted by
tolkiennut
I've flown infant in lap on UA before, and they issue a paper boarding pass for the infant in lap for the entire trip, so I wasn't sure what happens if they issue one for segment 2 and it goes unused...
Only if you add the infant in lap to the entire trip. My understanding is you can selectively add it to each segment. For the segments where the child is added, yes, UA issues a separate boarding pass. (Some other airlines simply place a notation on the adult's BP.)