Deleting notes won't happen, apologies. The database they are stored in relies on sequential ids and deleting a note requires we re-id all the notes and that requires reading/writing to disk for all the notes that came after it (by you, or anyone else). The last time I ran the admin command to delete a note we crashed the MOO because it took so long and maxed out the CPU. It's not the best system. It's actually got many many more notes in it than we ever dreamed. Good job players, but also, yeah, system limitations.
Also, I agree with the fact that deleting notes would be confusing for GMs.