I just tried to compile with the release version of simfactory (on Gordon but that would not matter) and I get:
[rhaas@gordon-ln1 Cactus]$ ./simfactory/bin/sim build --thornlist thornlists/NsNsToHMNS.th Error: required key email in section hal1 is missing Aborting Simfactory.
The same happens for the "user" key as well.
This is most likely hidden for most users since keys in the [default] section of defs.ini.local hide this issue. email may make sense to specify in defs.local.ini but user would not seem like something that should be left to default since it is machine specific.