Implantable medical devices (IMDs), and methods for use therewith, reduce how often an IMD accepts false messages. Such a method can include receiving a message and measuring a message interval indicative of a length of time between when the message was received and when a preceding message was received. The method can also include determining, based on the measured message interval, whether the message was received within the message window, and determining whether to reject the message based on results thereof. The method can also include adjusting a temporal position of the message window based on the measured message interval. The method can further include determining a quality measure indicative of a quality of the message and/or a quality of a channel over which the message was received, and determining whether to reject the message based on the quality measure.
