People sit on the curb watching an event.
A group of people watching a parade.
The word people does not always refer to a group of people. Just because people sit on the curb watching an event doesn't necessarily mean the event is a parade.
exists e2 e1 x1 x2 x3.(n_curb(x2) & for(e1,e2) & Theme(e2,x3) & Actor(e2,x1) & v_watch(e2) & n_event(x3) & on(e1,x2) & Actor(e1,x1) & v_sit(e1) & n_people(x1))
exists e1 x1 x2 x3 x4.(a_topic(x1) & of(x1,x2) & Theme(e1,x4) & Actor(e1,x3) & v_watch(e1) & n_parade(x4) & (x2 = x3) & n_people(x2) & n_group(x1))