Thank you Buddy1969 for your calm, level-headed and conciliatory contribution to this discussion. Of course I totally agree with your statement about the dangers of earphone volume with these devices. However I suggest that the law can be complied with surely, while allowing the user to turn off this feature if they wish. There could even be a legal disclaimer associated with turning it off, which I wouldn't mind, as long as the user is at least given that choice. All I suggest is this solution offered by Google is not the only one, by any means, when considered with a small amount of creativity and openness, and I would like to think Google would take its users' comments in this regard into consideration, and apply such creativity and open thought to the problem.
And I disagree that the solution offered by Google is a mere "inconvenience" as you say, and I would add that the nature of this "solution" is in itself in fact dangerous. Perhaps you are not a regular user of your device as an audio input in the car stereo, but as such a user I can say that the difficulty and potential hazard here is beyond "inconvenience". In order to have an audible volume over my stereo (when it is set at a reasonable volume) the volume on the device must be full. If played at the recommended level for earphones, the stereo volume must be set so high that when switching to another input such as radio or CD it could potentially blow the speakers or cause a major distraction to the driver. And the fact that it is inaudible when the amplifier is set to an acceptable volume means one can plug it in and drive off expecting something to play, and then, when there iis no sound, be distracted by the fact that the volume on the device is not increasing as expected. Such distractions are the cause of road accidents and must not be underrated.
Therefore there needs to be a better solution as the current one is potentially just as dangerous as the "problem" it is trying to solve.