searching Taxonomy hierarchy

Hi,

This bit applies to drupal 6, but possibly to later drupals as well,

More than once, clients have been upset at me, that clicking on a parent term for a taxonomy hierarchy wouldn't search it's children. See it's always the developer's fault, never the client's expectations.

Well the Hierarchy I'm working with for our current client is a Province / Canton / Township hierarchy. And boy do they want to be able to search the entire Province via the Taxonomy.