Wh movements
When a sentential complement contains a double object verb whose objects are both wh phrases, a derivation that violates the SCC. In the derivation (1), GIVE represents either the finite or the nonfinite verb form.
(1)

If GIVE is construed as finite, we derive (2a) from (1); if it is construed as nonfinite, we derive (2b).
(2)

Either way we interpret GIVE in (1), the result violates the Opacity Principle. This holds for the other possible derivation from (1a) and also for all derivations in which the indirect object is moved into COMP from a prepositional phrase (whether or not the preposition is also moved into COMP). In (1d), ti in S2 is in the domain of a subject (Mary) and cannot be properly bound by its antecedent whoi in the external COMP1. (2a,b) involve violations of the SSC, and (2a) involves a violation of the TSC in addition.
What (2) shows is that multiple binding into opaque domains is prohibited by the Opacity Principle when this binding involves the same escape hatch. The Opacity Principle does not prohibit multiple binding into opaque domains when the two different escape hatches are used. Thus, (3) is perfectly grammatical even though its surface structure (4) contains two bound traces in the complement predicate.
(3)

(4)

The two traces in the complement predicate are properly bound by the two traces in the escape hatches (complement subject and COMP), and the latter two are properly bound by their lexical antecedents—all according to the Opacity Principle.