In the current WebAudioAPI spec, nominal ranges are given for each possible AudioParam such that if the AudioParam is set to a value outside the range, the value is clipped to one of the end points.

This is a bit annoying if you accidentally set the value outside the range because there's no indication that you did something wrong.

The spec doesn't say errors should be thrown, but it would certainly be useful if a warning is printed if an attempt is made to set the value outside the nominal range.  This only applies to the AudioParam setter.  The automation methods (and the compound parameters) can't do this because the values are all happening in the audio thread.