  Consider a classically chaotic system which is described by a Hamiltonian
H_0. At t=0 the Hamiltonian undergoes a sudden-change H_0 -> H. We consider the
quantum-mechanical spreading of the evolving energy distribution, and argue
that it cannot be analyzed using a random-matrix theory (RMT) approach. RMT can
be trusted only to the extend that it gives trivial results that are implied by
first-order perturbation theory. Non-perturbative effects are sensitive to the
underlying classical dynamics, and therefore the hbar-->0 behavior for
effective RMT models is strikingly different from the correct semiclassical
limit.
