Function strict_write_for 

pub fn strict_write_for(
    conn: &Connection,
    user_id: &str,
) -> Result<bool, String>

Whether writes for this user must satisfy every scope rather than any.

True when the user or their class has it set. The OR is deliberate and is the fail-closed direction: a class that exists to constrain a group must not be looser than the group, and an individual asked to be strict must not be relaxed by their class.