On the other hand, it's not too surprising that tourists don't know very much about geisha and maiko, and Kyoto uses geisha in their tourist advertising, so it's understandable that these tourists would be pretty ignorant.
That said, if I remember correctly, geisha and maiko have been falling in significant demand for some time. Perhaps the best way to deal with the situation is for the city to come to some sort of agreement with the remaining geisha houses to allow tourists some kind of official access to the geisha for photos in a controlled environment. The downside, of course, being that I'm sure geisha themselves aren't interested in being reduced to a tourist attraction.
The site also notes that the BBC article doesn't specify that it was foreign tourists, although the Japanese article that they probably got their information from does-- oh, media.