Several people rock hiking with backpacks and walking sticks.
The group is attending a concert.
Attending a concert is different than hiking.
exists e1 s1 x1 x2 x3 x4 x5.(a_topic(x1) & with(x1,x3) & subset_of(x5,x3) & n_stick(x5) & Actor(e1,x5) & v_walk(e1) & subset_of(x4,x3) & n_backpack(x4) & n_rock(x1) & Time(x1,x2) & n_hiking(x2) & n_people(x1) & a_several(s1) & Theme(s1,x1))
exists e1 x1 x2.(n_group(x1) & Theme(e1,x2) & Actor(e1,x1) & v_attend(e1) & n_concert(x2))