I was searching for something else on my iPhone by using the pull down search facility from the home screen. I was horrified for some confidential data to pop up in the search box, from within a locked note. I double checked and the data was definitely in the body of the locked note, not in the title and the note was locked. This is a serious security breach and something that Apple should tackle rapidly. There does not seem to be any option on Notes to exclude them from the search facility.