You're absolutely right Pete.
I had this conversation with a mate of mine when I was made redundant about 10 years ago. He suggested that we start up a trail riding business leading peeps around Salisbury Plain etc. I knocked the idea on the head straight off as you would end up getting sued by some 'hooray-henry' who thought it might be a jolly good caper but fell off on the first bit of mud and blamed me.
Plus what Fred said, it would just become a chore