The solution is to load your XMP template into the IPTC Stationery Pad, then uncheck the date field, then save the template and distribute as needed. If you save the XMP template from the IPTC Info dialog (NOT the Stationery Pad) and then load this XMP template into the IPTC Stationery Pad, then the Date field will be checked to apply. It has to do with the fact that the IPTC Stationery Pad saves out the array of "apply flags" but the IPTC Info does not. Without these specific apply flags, any field that exists in XMP (non-blank) will have it's apply flag checked when loading into the IPTC Stationery Pad, and since the date field is always written, it will always have the apply flag checked UNLESS you save the XMP template from the IPTC Stationery Pad and ensure the Date field is NOT checked. Additionally, when saving the XMP template from the Stationery Pad, you can have it always apply the capture time (from Exif), or today's date, etc to the XMP DateCreated field, regardless of any XMP DateCreated field present. You cannot do this if the XMP template is saved from the IPTC Info dialog.
We may try to add some kind of fix to NOT check the Date apply box when loading an XMP template (with a date) into the Stationery Pad and its "apply style" is set to something other than "Date" (e.g. Capture Time, Modification Time, Today).
Hope that helps...
--dennis