My experience is; those who should know about it, do. Of course, a lot of apps or web developers don't. And I think that is okay.
The bigger issue is code designed for float32 (for performance reasons) being assumed valid for float64 data. And in these cases the issue is always, what is the appropriate way to communicate to your user the intended use case of the function? When the writer is long gone, a user will not intuitively know. Whenever I have to use a 3rd party library (ahem, PCL). I peruse the code and grep for float variables... If I see too many, I simply assume I need to recenter my float64 to be near 0.0.
Not everybody has the experience for this diligence, thus it appears as if developers don't understand.