It's not strictly necessary, because references cannot be cv-qualified.

It caused some confusion here (in Barry's and Anton Savin's answer), so I suggested it might be clarified. Barry originally thought the removal of cv-qualification causes type deduction to recur with the non-cv-qualified type; Anton might have though both sentences apply as well -- in any case, both seem to have though that P == T const& will get stripped to P == T instead of P == T const. That's why I suggested it might be worthwhile to clarify it.

At the very least, the section could use an example. We get 7 examples for initializer lists, 3 for forwarding reference, but none for the "standard" cases - which aren't necessarily trivial.