Question Author
I will check of course, but I found this in Mamyalynne's link.
Reciprocity is the country or state being visited recognising the Parking Permit of a visitor from another country or state, and granting to the visitor the same parking entitlements given to its own disabled citizens. There are two international agreements encouraging countries to recognise the Parking Permit of a visiting disabled person:
The member states of the International Transport Forum (ITF): EU and EEA, along with USA, Canada, Australia, New Zealand, Japan and Korea, have agreed in principle to reciprocity for each others disabled citizens: "To provide people with reduced mobility with a document (Parking Card / Permit) _ _ _ and to give the same parking facilities to holders of this document coming from another member or associated member country as they do to their own nationals" (ECMT (now ITF) Resolution 97/4)