RESTful API - Correct behaviour when spurious/not requested parameters are passed in the request

Question

We are developing a RESTful api that accepts query parameters in the request in the form of JSON encoded data.

We were wondering what is the correct behaviour when <

Answer 1

Just ignore them.

Do not give the user any chance to reverse engineer your RESTful API through your error messages.

Give the developers the neatest, clearest, most comprehensive documentation and parse only parameters your API need and support.