  In this essay it will be shown that Decoherence Model and Einstein
Equivalence Principle are conceptually incompatible. In other words, assuming
only the validity of the Weak Equivalence Principle the present work concludes
that we face two possibilities: (i) if Decoherence Model provides a correct
description of nature at quantum level, then there are systems which violate
Local Position Invariance, or, (ii) if all the postulates behind Einstein
Equivalence Principle are valid, even on quantum realm, then Decoherence Model
breaks down in curved spacetimes. Finally, the present results are confronted
against Schiff's conjecture.
