CCK field tokens do not work if set as Hidden in Display Fields

Issue Summary

Use case: node type for Person, with prefix, first & last name and suffix fields.

Desired behaviour: When entering content, these four name fields are entered separately and the node title field is hidden. auto_nodetitle then generates the node title from these four fields:
[field_name_prefix-formatted] [field_name_first-formatted] [field_name_last-formatted] [field_name_suffix-formatted]
When displaying the node, the node title is shown but not the individual name fields.

Actual behaviour: If I stop the individual name fields from displaying by setting them to <Hidden> at admin/content/types/person/display , the token substitution stops working for those fields.

I could work around this by creating a template for the Person node type, but AFAICS the above approach ought to work.