List with flagged/not flagged content of another user

I want to create a list with nodes, where administrator can see which nodes are flagged/not flagged by a user.

What I do:

Create a views page with nodes.
Display as Table.
Set views path to user/%/flags.
Add relationship to 'Flags': Uncheck 'Include only flagged content', Choose target flag, Check 'Any user'.
Add field 'Content: Title'.
Add filter criteria 'Flags: Flagged': Expose this filter to visitors.
Add contextual filter 'Flag: uid': Default argument "User ID from URL'.

What I get:
When 'Flagged' filter is set to 'True', I see all the nodes flagged by user.
When 'Flagged' filter is set to 'False', I see no results.

Expected: I would like to see all the nodes, that are not flagged by the user.

Conclusions: of course I will not see unflagged fields of the user, because contextual filter makes user ID required field.
Possible solution: add user ID to relationship's JOIN conditions.