
DO NOT DO GEDCOM IMPORT! Instead, use SmartCopy - https://www.geni.com/projects/SmartCopy/18783
SmartCopy allows way more control - update existing profiles, only create new profiles for ones that do not exist.
Importing creates a gazillion duplicates all of which need to be merged - after which for each field that had a value , you have to choose which is the correct value in the Conflict Resolution Screen if they differed.
https://www.geni.com/projects/Connecting-to-the-Big-Tree/17983
has
"If a merge involves a profile in a standalone tree, the merge will be pending until it is approved by a manager or collaborator in the other tree."
However, Geni's rules have changed, and Curators can complete requested merges to a Public Profile in a Standalone Tree.
So that statement is a false promise, and may explain some of the upset when standalone trees are merged in.