Hmm, I'm tempted to change the config option name to something like `fieldSpec` because you're absolutely right, it's quite counter-intuitive.

The reason it's `email: false` is because that object gets passed directly to mongo's `find`/`findOne` methods, which accept `fields` as their second argument and use that object to show/hide fields, see [the node-mongodb-native docs](http://mongodb.github.io/node-mongodb-native/api-generated/collection.html#find) for more details. So in this case `email: false` means don't include the email field.

I think perhaps changing the option name and being more explicit/obvious about this in the docs is the way to go.