We consider asymptotically future de Sitter spacetimes endowed with an
eternal observatory. In the conventional descriptions, the conformal metric at
the future boundary I^+ is deformed by the flux of gravitational radiation. We
however impose an unconventional future "Dirichlet" boundary condition
requiring that the conformal metric is flat everywhere except at the conformal
point where the observatory arrives at I^+. This boundary condition violates
conventional causality, but we argue the causality violations cannot be
detected by any experiment in the observatory. We show that the bulk-to-bulk
two-point functions obeying this future boundary condition are not realizable
as operator correlation functions in any de Sitter invariant vacuum, but they
do agree with those obtained by double analytic continuation from anti-de
Sitter space.Comment: 16 page
