A really great app is available as well. I'd explain but here's a link that's more eloquent than I am: http://www.salon.com/2013/11/21/this_incredibly_smart_domestic_violence_app_could_save_womens_lives/
Although a Snopes article presents a slightly different viewpoint on it:
http://www.snopes.com/2015/06/29/aspire-news-app/
Overall, it could help some.
RE: On a Serious Note, If you ever see a black dot on someones Hand