Well when one comes falling out of the sky because the battery died or whatever and it drops on an unsuspecting crowd on the boardwalk then that video demonstrates the potential carnage it can cause.
Its relevance in regard to this thread is the novice operator in a public space plus the injury he sustained. This could have happened to someone on the Seattle boardwalk or anywhere just the same, see other video I posted.
This isnt a stretch or leap to see what could happen unless we just need to see a new video of a catasrophic incident caused by a drone in order to prove the point. Lets be proactive and not reactive.