Under the default security rules users should not be able to see each other's unpublished sheets. The Stream security rule is the only one that grants access to published apps and app objects that you do not own.
Can you share more about the rules you have configured in your environment?
Here is the security rule that I wrote to not being able to see other people base sheets in our production environment. It is not working as expect.
!resource.App.stream.Empty() and resource.App.HasPrivilege("read") and resouce.resourcetype="App.Object" and (resource.ojbectType="userstate" or (resource.objectType=!"sheet" and resource.published="true" and user.roles="Consumer"))
I would like for a user to create a sheet; however, limit the ability who sees them preferable the owner of the sheet. I do not want everyone to view all the sheets under My Sheet section. Can anyone assist in writing a security rule that only shows those sheets to the creator only rather than show all of my sheets?
You'd need to write a rule to *allow* people to see other people's sheets, since this is not allowed by default. Find out which rule is currently doing this, and modify that rule so it no longer does this. You won't be able to fix it by adding a second, more restrictive rule since the original rule will still allow access.