I think they should be more concerned with public safety. If the couple asks them to stop, maybe but if they are slow to respond to those calls because of the history, they're going to get skewered when a real call comes in.
Maybe the police should ignore anonymous calls for that house.
The couple is likely fine with the police not going there for anonymous calls. What's the danger here, they are being held captive and the only call that notices the police is anonymous?