How to deploy Azure RM template without providing variables that have default values defined?

I would like to deploy a template from the Azure Resource Manager QuickStart Templates.

Many of the templates there have a default value specified in the template file (for example this one azuredeploy.json ):

"ouPath": {
  "type": "string",
  "defaultValue": "",
  "metadata": {
    "description": "Specifies an organizational unit (OU) for the domain account. Enter the full distinguished name of the OU in quotation marks. Example: 'OU=testOU; DC=domain; DC=Domain; DC=com"
  }
},

However, the corresponding azuredeploy.parameters.json does not define the ouPath value.

When I specify the file in --parameters-file in the Azure CLI call:

azure group deployment create "${resource_group_name}" "${deployment_name}" --template-uri "${template_uri}" --parameters-file ${parameters_file}

I get an error:

info: Executing command group deployment create
  error: Template and Deployment "parameters" objects lengths do not match
  Deployment Parameter file does not have { ouPath } defined.
  error: Error information has been recorded to /Users/techraf/.azure/azure.err
  error: group deployment create command failed

If I define add the value explicitly to the parameters.json file, the deployment works properly.

Main question:

The sheer number of examples (parameters.json) in the above Azure repository without explicitly specified values makes me think, there must be a way to tell Azure to use default value instead of providing it in parameters.json.

Is there a way to avoid adding the values that have defaultValue defined in the template file when using Azure CLI?

Additional question:

Worse yet, in the example I have given above, the default value is empty and if I specify an empty value in the parameters.json:

"ouPath": {
  "value": ""
},

I get an interactive prompt for the value.

How can I avoid that?