I would upload a statement or a letter to the NVC explaining that she does not require the police certificate, and highlight the relevant sections of law like @powerpuff suggested. This will help you not get an RFE (hopefully - because and RFE will slow down your case). BUT - I would request the police clearance certificate now so that when the interview stage comes along, you have it. It's better to have it and not need it than to need it and not have it.
