You can also be injured, left behind, faint, stop to help someone, etc.<p>A drone that can follow a trail that changes quite a bit over the year and is trained to recognize obvious trail signals (jacket on tree, reflectors) or human voices offtrail as it passes (&quot;help! over here!&quot;) would be excellent. A drone pass at closing time might become a standard precaution and CYA thing for parks, plus they can give trail notes like where it&#x27;s poorly marked, blockage and collapses, and so on.