Nice to have the related data option in AGOL, especially for Field Maps 'inspections'.
However, to publish a hosted feature service that can be utilized for this, and be able to append data while preserving GlobalID, one must have a unique index on the GlobalID field in the related table.
However, Unique GlobalID indexes are NOT supported in FGDB, but are in mobile Geodatabase. But, can't publish stand alone table from a mobile geodatabase as they are not supported. So, the only way to do this locally is with SDE data.
Please allow us to publish stand alone tables from mobile Geodatabases OR allow unique GlobalID indexes in FGDB.
R_
