Excellent post by Michael Kelly but for the web version of Survey123 I don't think this will work...unless you're planning on extending the limited pulldata functionality in the web version to geopoint questions soon?
Might there be another workaround that requires the observer to do something with the map control (pan, zoom,etc) in order to show "success" on this required field? Because I'm centering the map in Connect, the default center location is being used to fulfill the "required" condition and the user isn't forced to make changes to this location before submitting.