It's not necessarily the tin foil, per se, as that he is often menacing or angry in his approach. It varies, on what factors we can only guess. The foil may simply be a way of looking scarier, rather than the presumed attempt to screen out voices. Either way, we try to avoid direct interactions when possible. Unfortunately, one of his favorite approach methods is to wait for pedestrians who are waiting at the light to cross a street downtown. Since he doesn't appear to have been arrested, or at least, to have been kept in jail for an extended period of time, he's probably not been physically violent with people.