It must be possible for users to submit unnested POST requests and get the object created. However some (all?) API/v2 controllers beg to differ.

This can be replicated for all properties of api/v2/interfaces, api/v2/external_usergroups, and possibly other controllers.

curl -X POST -u dlobatog:xxxx -H "Content-Type:application/json" http://localhost:3000/api/v2/hosts/19236/interfaces -d '{"domain_id":13232}'

{
  "error": {"message":"domain_id is not allowed as nested parameter for interfaces. Allowed parameters are host_id"}
}