Please read this short article:
I often tell my students that you have to think that an attacker could be armed. We can't simply train to block a punch.
I'm not saying that we are capable to defending against a machete attack without getting injured. What I am saying is that we have to think that an attacker could use a machete or other weapon. A small knife could easily be concealed. Because of this, avoiding the conflict, if possible, if the best strategy. And being aware of the situation is essential. Even a second or two of advance warning could be critical. It could give you the time to escape or use something in the environment as a shield or self defense weapon.
Charles C. Goodin