I guess if you want to be confrontational then you can say get a warrant. There are too many variables that could or could not be present which could get a law enforcement officer into a house without a warrant. At that point, you will know if they have pc or not because they will either leave, get a warrant, or search anyways.
I usually tell most people what my pc is but you don't have to (it's just the nice thing to do). Again there are bad apples, but Integrity should stop that and if it doesn't then they will get caught up in internal affairs sooner or later.