Answer
No — context/scope mapping is purely a client-side personalization mechanism for giving users a tailored view, not a security boundary. A user assigned to Scope A only sees Scope A's changes by default, but if they know to append the scope parameter to the page's URL (for example, appending a scope query parameter naming Scope B), they can view another context's configuration directly, bypassing whatever fields that context hides. Page configurations and contexts should never be relied on to actually restrict access to data or fields — genuine access control has to be enforced through permission sets and other real security mechanisms, since context/scope switching via the URL is trivially possible for any user who knows about it.