I'm debugging a problem I'm having with the location_cck module (part of location's contrib modules), where the default value for a field gets displayed in the node edit form, but is not actually processed -- content module zeros out the field during the presave pass in hook_nodeapi. Edited content, however, does get saved away, even if the edited content is the default value. I've reported this problem on location's issue queue, as #416230: Location CCK field does not set default location.

Part of the problem turns out to be that location_cck is not really all-the-way updated to the 6.x-2.x apis, so to see if I can get my installation to work, I'd like to try to make that conversion. The current version of the handbook recommends using a hook_default_value for this, but I've noticed that this is not being widely used. Even more than that: I've noticed that some modules, including imagefield.module, have actually removed code that use hook_default_value in the last month or so.

I'm guessing that these developers know something I don't, and that isn't currently documented anywhere.

Could someone please give me a little history here, and point me to samples of how to do default value processing in current releases of CCK?