There was one time I was glad someones brakes were squealing.

Three of us were mountain biking in Jasper National Park. One of my friends went over the bars near the end of a 20 mile ride. When we got back on our bikes and went around a corner a bear was on the trail. I think it heard us coming thanks to the odd squeal of brake pads. As a result it wasn't startled and the three of us didn't end up a statistic on a chart somewhere.