For my use case and general good practise I would prefer that the api threw an error if an invalid CQL parameter is passed. This helps because users of the API are more aware of what is and isn't being applied. In the case of using these APIs within a workflow, a mis-spelled parameter can ultimately lead to erroneous data, further downstream, without the knowledge of the end user. I have a fix for this and can push it up if given access.
input-parmeter-validation-diff.patch