What sort of security vulnerability would justify this extra paranoia? The worst case is that it's something which affects the very-common case of postgres serv

What sort of security vulnerability would justify this extra paranoia? The worst case is that it's something which affects the very-common case of postgres servers that only talk to local services, like a unicode or quoting error that made sites which nominally quote their queries correctly vulnerable to SQL injection. That would be as serious as the recent Rails vulnerabilities: drop everything, patch everything everywhere, or definitely be rooted. Be ready to patch as soon as it's out; this could be a big deal.