I love this. Long time ago, I tried to see if I could do a similar project but never got far. It was not for Human trafficking victims but was for the entire female population of South East Asia counties, esp. India where assaults on women and rapes are really common. I think a similar texting service can be setup for women in countries like India to call for help if possible or at least report it (maybe anonymously?). In a country where Police is basically useless, this will at least come in handy if there is enough data pouring in and maybe citizens can help each other by watching out for a particular place that is unsafe.
I'd really like to work for such a project.