Private files were being transferred to Mundia but it was a mistake and should not be happening now. I only went on it long enough to make all my trees there private and unsearchable. The bad part when "they" did it is that even trees that I was a GUEST in that were private got transferred as my trees. This all WAS in error and hopefully was fixed.
You can't prevent someone from copying stuff if your tree is public. You can't really make a branch private. You CAN make individuals private, or certain other things private for instance my tree is public and I sync, but the actual media I pay for from Scotland's People I make private. Also you can make some facts private for a person and some public.