Some chocolate fountains can be sanitary while others are not depending on its placement and the rules on using it. Do not allow people to use their fingers, you can instead put long toothpicks for the guests to dip their treats. Wearing gloves after careful washing of hands is also important. More details at http://www.ehow.com/way_5262674_chocolate-fountain-ideas.html.
Not really because everyone is putting their food under the same chocolate as you, and if they use their fingers they put their germs in the fountain. I would only use a chocolate fountain at like a small party or holiday dessert.