  By using very general and well established features of soft strong
interactions we show, contrary to conventional expectations, that (i) soft
final state interactions (FSI) do not disappear for large $m_B$, (ii) inelastic
rescattering is expected to be the main source of soft FSI phases, and (iii)
flavor off-diagonal FSI are suppressed by a power of $m_B$, but are quite
likely to be significant at $m_B\simeq 5$~GeV. We briefly discuss the influence
of these interactions on tests of CP-violation and on theoretical calculations
of weak decays.
