Consider the following (idealized) chart.
Now, I have worked with colleagues from every side of this spectrum and have learnt that, unfortunately, it tends to be more like this.
Most "web developers" tend to know very little of design principles while, on the other hand, "web designers" tend to know very little of the technical side of the web. Well rounded "web crafters" are hard to find.
This unfortunate but real scenario makes creating a responsive website for a team of developers and designers a pain. Web designers tend to forget the site should adapt to every possible commercial device and often design rigid layouts that look great on their own screen but are impossible to turn into responsive websites. Developers, on the other hand, tend to make brutal adaptations of the designer's vision trying to achieve responsiveness.
Where should the responsibility of designing a responsive website fall? Should the web designer be expected to provide well thought guidelines for the developer on how to adapt the website for every possible scenario? Or is this an unreasonable expectation?
Please notice I am focusing on the design side of it, not on the developing side of it.