Well, that's why a lot of suggestions are to make it a user option, which is the best solution. As to how I personally hit the delete button "accidentally", I am often editing a search in the text search box, and pressing <delete> to delete some of the text in that box (<delete> on a Mac is backspace), and for some unknown reason at random times Evernote will change the "focus" of the action from the text box to the list of notes. So I start by deleting text in the search box, and I end by deleting a bunch of notes without noticing it. I haven't figured out exactly what causes the focus to change from the text box to the notes list, it could be position of my mouse, or another application doing something, but the point is that it is very easy to delete a note when in fact you intended to delete text in the search box.