In an ideal world, all machines would have perfect connectivity to the network at all times and servers would never crash. In the real world, it may be necessary to avoid hitting the network and have Polipo serve stale objects from its cache.
true prevents Polipo from
contacting remote servers, no matter what. This setting is suitable
when you have no network connection whatsoever.
proxyOffline is false, Polipo’s caching behaviour is
controlled by a number of variables documented in Tweaking validation.