"From my experiance, a majority of guests leave because of the fear of confrontation. They react better on the phone or email and would rather handle at a later time. It's the managers duty to correct everything then."

That's a very valid point. See the letter to IHOP (also in the Top 25 at present) to see how it can go the other way. There's a good reason people don't like confrontation. It might go well, or it might not. Even without that element of uncertainty, the discomfort of engaging in a confrontation (which can be quite extreme for some people) places an unnecessary burden on the already offended party.