make a note not accessible

[Kreekakon]

Or try placing a blockbox on the note itself. It is in "technical" in the level editor. Invisible in-game, but visible in the editor. Not sure if this works, though.

It works, although it's not viable if you want the note to move for whatever reason.

If all you want is a "piece of paper" in your map, there are a few things which can substitute for that in the editor which are not notes.