Also, it has been true for centuries that a woman screaming "help!" would draw the attention of all the men in the area (for example the carriage driver in this case) who would be eager to beat the other man to a pulp if he didn't stop harassing her.
Women and children first into the lifeboats, remember? Most men do care about women as a class and even elevate their care for them above their concern for themselves.
Also, although people might give a 5'1" man some leeway regarding using a stick against a 6'2" man if the 6'2" man attacked him first, I don't think anyone would find it acceptable for the 5'1" man to INITIATE the violence using a weapon merely because of the POSSIBILITY that the larger man might attack him.
If you're in a bar and a large man says something insulting to you, do you just skip to attacking him because, if you say something insulting back he might attack you? If you do, I'm pretty sure you're the one who will be charged with a crime.
You know, sometimes people who ask for directions then demand your wallet. Should I just attack everyone who approaches me for directions, because they might be a thief?