For years some people have avoided sunroofs because they can be a source of leaks. Personally I’ve never had one leak. But now that I’m conducting this research, I’ve learned that some of them do leak.

Actually, it seems that sunroofs are designed to leak a little, just not into the car. Instead, a tube is fitted to the gutter below the seal, to drain any water that does get past the seal. When water nevertheless ends up inside the car, the reason is often that this drain tube has become crimped or plugged up.