Robbery on the roads - highway robbery - was a common crime in this period. There were few banks, so people carried lots of their money around with them. Britain was a rural country, with few large towns. Roads were not made up so travel was slow and there were few travellers. Roads were therefore quiet, with lots of isolated country places, even quite near towns. There was no police force.
Highway robbers rode on horseback, in order to stop and chase their victims, or get away quickly. Riding on horseback was supposedly the mark of a gentleman, a mark of class. Highwaymen therefore had a reputation as classy criminals: courteous to women, well-mannered and honourable. Does the evidence support this ideal?