I think that trend is being reversed slightly. Within the last three or four years, I think countries have been afraid of being put on the OECD grey list and black list. For example, you saw Switzerland adopt, at least with the United States, a new protocol on information exchange that dramatically widened the scope of the types of cases in which information would be disclosed.
But as Mr. Sohmer points out, correctly, these treaties still prevent what are called “fishing expeditions”, which puts a significant crimp on the ability of a requesting state to ask for information. If you can't name the client or the bank, you're in trouble.