BG was comfortable walking on that bridge with his hands in his pockets. Most of us need our arms to keep our balance while walking.
I thought I remembered that the reason the girls were filing was to make money to go to the mall that day, is that true. if so, why change of plans to go to bridge.
Girls were up super late, 2-3 am making musically videos online. Surely this was a great opportunity for BG to discuss meeting the following day. Perhaps he said first, 'let's meet at the mall' to make it sound safe and then changed plans to meet at bridge.