Sometimes a black bar or even cropping isn't sufficient. You still have to trust the editing software.

There was a scandal around 2003 when a TV host took a topless photo, cropped it and shared the cropped photo online. Unfortunately, the software (Photoshop—I think CS3) she used to crop the photo stored the original photo as metadata if you didn't change the original filename. The original (uncropped) photo could be seen in the "Open File" preview dialog when opening the cropped version.