You can over analyse this stuff.
Generally, you have a duty to take reasonable care for the safety of other folk who might foreseeably be adversely affected by your actions. (Or inactions, sometimes.)
That's why when you're out driving your car, if you pile into the back of another car, it's your "fault" - ie you've failed in your duty of reasonable care to the unfortunate motorist in front - and the affected party has a claim against you. In a car of course you are - or should be - insured for that very occurrence.
If you guide folk up a hill, as an informal favour kind of affair, then you owe those people the care that a reasonably careful chap guiding folks up a hill on an informal basis owes them. (The duties owed by professionals - whether it be mountain guides or doctors - can be a whole different kettle of negligence.)
If you make a mistake, and someone suffers loss injury & damage (as they say) as a result of that mistake, then yes, you are at risk of getting sued if someone's motivated enough. And indeed, whether you're up a hill or not, if you make a mistake and someone gets hurt as a result, why
shouldn't you get sued?
Which kind of brings us back to insurance.