Question about cross-staff beaming, unnecessary rests, Debussy

Question

Two questions:

1) Why in Debussy's Arabesque No. 1 the first two measures written without the rests? What's the rule?

2) If I write notes in different clefs and beam them together, what clef will they belong to? I mean, in programs that I used (such as Musescore and Sibelius), you cannot do this. Still, you can write notes in one clef, beam them, and send some of them to another clef, and this is the only way you can do cross-staff beaming. But the problem is if, for example, I input the notes in the Bass clef (let's say G2-Bb2-D3-G4) beam them and then send G4 to a Treble clef, the notes are beamed and look how I want. However, that G4 that I sent still belongs to the Bass clef and the programs add unnecessary rests from both sides. How to deal with it?

Answer 1

Yes, when a musical phrase crosses staves it's conventional to leave out the extra rests.

At present, in Sibelius at any rate, you just have to manually hide the unwanted rests.

Here's what Gould has to say on the subject.

Answer 2

The only "rule" is that the notation should be as clear as possible. In the Debussy example, it's very clear that there's one monophonic line that meanders across both staffs (and therefore, both hands). Omitting the rests helps clarify the line a little bit. You might also see examples where a second voice within one staff starts midway through the bar, but the engraver chooses not to show the rests that "should" buffer it out, instead relying on vertical alignment for clarity. In a way, rests only need to be there for accounting purposes, and if the accounting can be accomplished in other ways, less ink on the page can be cleaner.

Your software will insist on having the rests for accounting, at least internally. You'll need to select the rests and make them invisible. I'm not very familiar with Sibelius or Musescore, but in Finale it's the "show/hide" option (hotkey 'h').