Here's a wish for a config setting to optionally not write new geolocations to image tags, for people who lack permissions or wish to preserve original image files.

Currently, if user lacks write permissions to an image file, adding a new geolocation returns an write error for the image tag, but correctly writes the geolocation to the "imagepositions" table in the database.  Thus, aside from the error, all other geolocation features function normally.

Perhaps this requested option could be added to the menu at:

     Settings > configure digiKam... > Metadata > Behavior