Decks get forwarded
More than any other format, a slide deck is passed on. Each recipient sees the same properties: who made it, which company they work for, when it was last touched, how many revisions it went through. A deck sent to one client is often forwarded internally several times before anyone reads it closely.
Speaker notes are the real exposure
Notes are where the candid version lives: what not to say, which number is soft, who in the room to watch. They are invisible while presenting and plainly visible to anyone who opens the file. They are content rather than metadata, so cleaning does not remove them and you should read them yourself before a deck goes outside.
Hidden slides stay in the document
Hiding a slide excludes it from the slideshow and nothing else. It remains in the file, appears in the thumbnail rail, and is one right-click from being restored. Decks routinely carry a hidden appendix of pricing that was hidden rather than deleted.
Objects dragged off the canvas
Anything moved outside the slide area is invisible on screen and fully present in the file. The Selection Pane, under Arrange on the Home tab, lists every object on a slide whether or not you can see it.