Just to be clear, @dsyphers you still want to raise a `ValueError` with no option to override for `x < 0.3` and `x > 11`? The warning is only for when you want to extend *CCM* beyond the recommended range? I'm looking for consistent behavior for a wavelength outside of the recommended range of whatever model is requested.

I don't know if turning warnings on and off via a keyword argument is the "right" way to do things in astropy. Pinging @eteq and @astrofrog for clarification on the right way to silence particular warnings.