Certainly, the woman is a self-appointed tourist guide because she pesters the speaker to avail of her services even when his intention is to get rid of her. Her persistence is seen in the fact that she hobbles after him and goes to the extent of stopping him by tightening her grip on his shirt. The speaker is more and more annoyed and he wants to get rid of her by being firm in refusing her offer. If we compare the interaction between the speaker and the old woman, we see that it isn’t much different from the transaction that takes place between a tourist and a beggar.
The beggars also follow people around pestering them with a demand for alms. But the difference is that if the tour guides offer their service, the beggars don’t. This immediately introduces a world of difference between the two categories of people. It shows that even if the tour guides can be as annoying as the beggars, they are people with self-respect.