The other customer would know it wasn't a one-off issue and feel more justified airing their grievances in a public forum since it may be a systemic issue. If

The other customer would know it wasn't a one-off issue and feel more justified airing their grievances in a public forum since it may be a systemic issue. If a burger king location served a burger cold once in thirty years of operations yea I still want a replacement burger but it's no biggie - if it does that dozens of times a day their corporate image deserves to be dragged through the mud. When it's a restaurant we regularly patronize we can offer the feedback directly with confidence about the severity, when it's something we use once in a blue moon (like an airline for most of us) we don't know if that poor service was basically par for the course.