It is apparently the case that a license was required to carry a cane in London during the 18th century, possibly because of the use as a weapon, in essence a fighting stick.
A particular type of walking stick was created, called a Swordstick. This concealed a blade within the stem, which can be made to appear from a cane so as to convert it into a (normally hidden) weapon. Today, sword sticks are called Sword Canes. Sword canes are great for those who are impaired or just want to "dress up" while still having the protection of a hidden sword.