This summer, an incident happened in New York City that shows how good instincts and rapid creativity can be helpful in emergency situations. Could you do as well?

On Aug. 19, Thao Nguyen was riding on a Manhattan subway train, when a man sharing the almost empty car decided to expose himself to her. Uncomfortable about the action, Ms. Thao reached for her cell phone -- and snapped a picture of the man. In an instant, it was the man who became uncomfortable -- so he zipped up and fled at the next stop.

Ms. Thao, in the meantime, took the photo to the police and posted it on Flickr, a popular Web site that allows individuals to share photos and comments. She also posted a link to the photo and a brief note on craigslist, an online community with special sections related to various major cities, including her hometown, New York.

According to the New York Daily News, by Aug. 25 more than 45,000 people had seen the posted snapshot -- a number that likely rose dramatically after the Daily News published the story on its front page.

It wasn't just her instinct to snap the picture that makes Ms. Thao a tech role model. It's also her instinct to follow up. She got off the train and went to the police.

You've heard me complain about how some technologies, such as cell phone cameras, reduce our quality standards. In this case, those same cell phone cameras raise the bar -- because they show us how we can use them as safety devices. In this case, it worked in three ways: It gave Ms. Thao evidence she could take to the police; it gave her a way to track down the man whose image she snapped (who was subsequently apprehended in early September); and it served as a deterrent, as it seemed to chase him from the train.

Many individuals supported Ms. Thao's cause online -- by linking to her Flickr page from their blogs, or simply posting supportive comments. But not all the comments were supportive. Many of the comments that I saw on craigslist would make a tomato blush. These too might have been instinctive; but that type of instinct we could do without. Both Flickr and craigslist allow adult oriented-postings, and that's OK. I don't question the openness of the Web sites. I do question the motives of some of the posters, though.

Here in Pittsburgh, the type of incident that happened on the subway car doesn't happen much, but based on Ms. Thao's comments and the postings of those who commented on her snapshot, it must happen all the time in New York subways.

I remember when women were instructed to carry mace to ward off attackers. Will the new propellant of choice be camera phones instead? In many ways it makes sense, because they are portable, easy to operate, and connect you with the outside world almost instantly. On the other hand, there's a movement to ban them in places where they could reduce privacy -- such as public restrooms.

Like other technologies, camera phones could be a boon in the right hands, a threat in the wrong hands. I bet Thao Nguyen was glad she had hers with her. Now all we need is technology that would associate the image with the street address of the person in the photo. It may be here sooner than you think.