At my old job there were two people with candy jars. One woman had an office with a door that she usually kept open. She mentioned once that people usually took a piece when they met with her but rarely just stopped in. I suspect this was partially due to the door and feeling like you may be intruding and partially because she was a talker and any interaction was going to take at least ten minutes. The other woman had a desk in an open area but in another suite across the courtyard from the main office. I was in the same suite and there were people who stopped by for candy a couple of times a week.