Would that be possible? In that way deleted notes can be recovered (much easier than having to query sqlite and using the command palette as mentioned in How to recover deleted notes), especially when they are deleted by mistake. I think that would be similar to how conflict works?
Notes that I do no longer consider "active" get transferred to an "Archived" notebook that serves as an intermediary step before deletion or long term preservation. You could call a notebook "Trash" and move notes inside if you want to have a reversible deletion process.
Automating this would be great, and also prevents accidental deletions.
That's the way I do it, too - but it takes a whole lot of discipline to remember to use the move function instead of just deleting
Also using a Notebook for Trash here. Instead of moving the note manually, I've set a keyboard shortcut to move the active note to the Trash (Archives, Recycle bin, or whatever your chosen name for the Trash Notebook happens to be) by means of the Quick Move Notes Plugin, it's worked well for me.