automatically protecting people with private browsing

A friend of mine recently suggested people donate to the Women’s Domestic Violence Crisis Service, whose website provides a quick escape button (like a boss button) for victims of abuse to get away from the site quickly. Unfortunately the button simply takes you to Google (via an image map, I wonder why?). It doesn’t manipulate your history.

For people in abusive relationships, leaving behind browser history saying they were accessing a site to get help could be dangerous (this is why there’s a quick escape button in the first place).

HTML5 includes a History API, which will let you manipulate the most recent entry, and you could just screw up all the site history, that would be annoying for other people. It seems like the correct answer here is private browsing or incognito mode. While the warning page could include instructions on how to activate incognito mode for your browser (and offer to screw up the history) one wonders why HTML5 doesn’t include a method to load a site private/incognito so websites could offer to stay out of your browser history? I’m sure it would prove very popular with porn sites, but it might also help to protect some people.