A day hiker is someone whose scope is limited to the hours between dawn and dusk.
Most of these people started out in day camp and were permanently stunted by the experience, which forced them to believe in strict boundaries and to fear the dark. If in doubt, you can easily identify day hikers because they wear clean new clothes. Day hikers have no idea what dirt is or how to use it properly.
Most day hikers are actually afraid of dirt, as well as trees, shrubs, birds, squirrels, bugs, and basically anything that does or does not move by itself unless it is made of asphalt, or concrete, or sheet metal, or plastic, and has a neon sign over it, or batteries inside.
Especially bears.
Day hikers love bears. Bears scare the snot out of them, and not in a useful way.
They love being told that stepping even one inch off the pavement will bring the bears to drool indecently onto their crinkly new Supplex cargo pants and Taslan parkas and then eat them.
This might be true. Could be. But it's bad for the bears in so many ways, including the inevitable indigestion.
Hey, but some of these fears are based on real facts, and why not this one?
Encourage day hikers to remain vigilant. Warn them about how even a dab of mud on a pants cuff can start them down the old slippery slope. Talk about body odor and what sorts of unspeakable things will follow them around with evil intent if they have any of it, even the merest whiff.
Use yourself as an example. Of what can happen to a person who ever stays out after dark, even once.
Ask them for food and water.
Ask if Dewey is still president.
Grunt.
Snort.
Pick your nose extravagantly, then demonstrate how to launch a snot rocket. Show them your eye booger collection. That should do it.
If not, then ask for money. Grin. Keep that demented gleam in your eye. Keep asking for money.
If none of this puts them off, then you may have new recruits. Good luck. Everyone needs luck these days.