Knives

I asked on an expat email forum not too long ago where I can go to get my knives sharpened. It turns out they don't have professional knife sharpeners here. There are peddlers that go around and play a special sound on a flute to let you know they are in the neighborhood. I heard this the other day while I was on my way back from doing some errands. How do people take advantage of this service?

1. I live in the back apartment of a posada and don't hear noises on the street. I wouldn't hear one of these guys even if he were in my neighborhood.

2. Am I supposed to carry my knifes around in my purse when I go out, in the event I happen to hear the knife sharpener?

Puzzling. There must be another option, I just have to search a little more.