When you open the App Switcher in iOS 9, Safari will automatically blank out the preview page if you happen to leave off while browsing in Private mode. In iOS 8, Safari would show the preview card, regardless of whether or not a Private browsing session was last engaged.
There is already an API available for third-party developers to blur out App Switcher previews to protect sensitive data. Some banking apps and other apps with sensitive customer data do this already. But Apple’s method for going about obscuring potentially sensitive web browsing sessions is a bit different. Instead of blurring out the page, Safari simply blanks out everything when the App Switcher is opened.
As you can see from the screenshot above, this change prevents prying eyes from scoping out what you were last viewing in the Safari browser. This will only work, however, if you’re currently switched to another app and you open the App Switcher.
If you open the App Switcher while viewing a private window in Safari, the App Switcher will work like normal, and the contents will continue to be displayed. It’s only when you are using another app, or are at the Home screen, that Safari’s private session content will be obscured.
What do you think about this new iOS 9 addition? Good idea or bad idea?