I note from this article that a draft of a report (PDF) commissioned by ICANN and carried out by JAS (Joint Applicant Support) Global Advisors includes a series of recommendations — ranging from alerting network operators by returning 127.0.53.53 as an IP address to, in extreme conditions, killing a delegated second-level domain — to deal with the issue of traffic intended for internal network destinations ending up on the Internet via the Domain Name System.
Instead of the familiar 127.0.0.1 loopback address for localhost, the report suggests "127.0.53.53". Because the result is so unusual, it's likely to be flagged in logs and sysadmins who aren't aware of a name collision issue are likely to search online for information about the address problems.
"Numerous experiments performed by JAS confirmed that a wide range of application layer software logs something resembling a 'failed connection attempt to 127.0.53.53' which is the desired behavior. We also confirmed that all modern Microsoft, Linux, Apple, and BSD-derived operating systems correctly implement RFC 1122 (albeit with variations) and keep the traffic within the host system, not on the network," the report states.