If you refuse a normal search warrant (a court ordered document), you are in contempt of court, which does carry a fine and potentially a jail sentence at the judges discretion.
That's why I don't see a difference on this particular point.
Technically perhaps, but in reality, the police are far more likely to gain forceful entrance to the property and since they gained entrance, you are extremely unlikely to be prosecuted for denying it.
They can't take a battering ram to your hard disk. Well, they could, but it wouldn't be an effective way of recovering the data...
