When you have plenty of kunai and other weapons, it really isn't that big of a problem.

[ Kakashi pats the harness he's wearing on his thigh to emphasize his words. It may be too complicated to explain that he also has plenty of other weapons locked up in scrolls he also carries, at least for this particular conversation. ]

Besides, to be a ninja is to become a weapon yourself. Things like kunai and shuriken are just tools. There are many other techniques that can be used in combat.