  The observed bimodality in radio luminosity in galaxy clusters is puzzling.
We investigate the possibility that cosmic-ray (CR) streaming in the
intra-cluster medium can 'switch off' hadronically induced radio and gamma-ray
emission. For self-confined CRs, this depends on the source of MHD wave
damping: if only non-linear Landau damping operates, then CRs stream on the
slow Alfvenic timescale, but if turbulent wave damping operates, super-Alfvenic
streaming is possible. As turbulence increases, it promotes outward streaming
more than it enables inward turbulent advection. Curiously, the CR flux is
independent of $\nabla f$ (as long as it is non-zero) and depends only on
plasma parameters; this enables radio halos with flat inferred CR profiles to
turn off. We perform 1D time-dependent calculations of a radio mini-halo
(Perseus) and giant radio halo (Coma) and find that both diminish in radio
luminosity by an order of magnitude in several hundred Myr, given plausible
estimates for the magnetic field in the outskirts of the cluster. Due to the
energy dependence of CR streaming, spectral curvature develops, and radio halos
turn off more slowly at low frequencies -- properties consistent with
observations. Similarly, CR streaming rapidly turns off gamma-ray emission at
the high-energies probed by Cherenkov telescopes, but not at the low energies
probed by Fermi. CR mediated wave-heating of the ICM is unaffected, as it is
dominated by ~GeV CRs which stream Alfvenically.
