Even if it were a notebook, it could end up in court. If someone sees you writing in a book and talks about it during discovery, you can end up with a court order to produce that book.
Discovery can even be more broad - "provide all written or recorded messages involving this decision" and if you "forget" about your private diary and it's later found out, that's a paddlin'.
Absolutely, they can be but your lawyers at least have a leg to stand on to push for exclusion. If they are just sitting next to the PowerPoint you gave on Tuesday, they will definitely be included.