The other point is that these days things can backfire.
I always stop, even if only to ask if they have everything they need and assist if I can.
However a couple of years ago I came across a couple of kids, one of whom had a trashed dérailleur.
They lived a fair way off, so I removed the dérailleur, shortened the chain to a single speed to get them home and let them use my mobile to inform parents of the delay. Put all the bits in a bag
Following day I got a call demanding my details as I had "wrecked" his son's bike by taking bits off it!
Luckily local bike shop supported me and told the guy in no uncertain terms that nothing I had done was contributory to the repair bill.