I am not sure how unusual this is, but I had never seen it: my gg grandmother's (Sarah) stepmother had in her will that Sarah, the daughter of her husband by his first marraige, was not now or ever to get anything. I thought that a tad wicked. Although there are reasons for this happening, Sarah was also sent at the age of about 14 to live with an aunt and uncle 400 miles away, so I have dubbed the lovely 2nd wife the wicked stepmonster.
Kath