A few years ago, I got into Montreal just as a light freezing drizzle was starting. And something similar. A bit later that evening, you could barely walk on the sidewalk. And unfortunately neither of us had brought our microspikes.

>A failure in a traction device

I have had a microspike fail--fortunately just out my door. But it's mostly not the end of the world. Especially if you also have a pole you can manage pretty well with traction just on one foot under most circumstances.