What will be defaulted is determined by the scope the saved view was saved with in addition to the role assigned to the user for example:
1.
A user with "SE" role is accessing a view shared with "SE" role and has "Use Role Lenses" enabled for "SE" role:

In this example the Scope is defaulting to "My Team's Team".
2.
The reason why the above view is defaulting the Scope to "My Team's Team" instead of "On Deal Team" for example would be because the view itself was saved with a Scope of "My Reports" see that chart below:

3.
In the above example, if you wanted to change the above view to default the Scope to "On Deal Team" you would need to edit the view and change the Scope to "All" based on the above chart: