Yesterday one of my female students (there are 19 females and 4 males in the program),we'll call her N, reported a disturbing but unfortunately somewhat common experience. She had been exploring her neighborhood in broad daylight when the man walking a few yards in front of her suddenly turned around and pulled down his pants. She continued walking by him, squishing herself as close to the wall of the house on the street, and as far away from him, as possible.
I saw her soon after the incident. I told her that she had reacted in an appropriate manner, since responding in any way (yelling, turning around and running away) would have given the man an opportunity to respond as well, and shown him that he had affected her in some way. Having had a similar experience myself last year, I had felt confused, shocked, and then just really angry afterward. I asked her how she felt about it, and she said she didn't know how she was supposed to feel. Another student, L, said her first reaction would have been to throw punches, but N and I sincerely doubt she would have actually done so, since in the moment you're just so surprised and taken aback.
Last year, another student had someone try to reach up her skirt, and others were groped in public places like subways and just walking down the street, or propositioned in a lewd and inappropriate manner. A friend studying in Italy also had similar experiences, so it seems that this isn't just an issue in Mexico. In most cases, the men did not seem crazy or emotionally disturbed. They just seem to think that they can get away with this behavior with foreign women. I doubt they would ever try it with someone from their own country.
As for preventing this kind of thing, it seems almost impossible, since the events happen during the day, when other people are around and in busy neighborhoods and public places, and they occur with almost no warning. I suggested that N not walk down that street again, but that's about as much advice as I can give her, aside from providing a sympathetic ear.