For what reason might an aircraft equipped with ADS-B not transmit?

An aircraft equipped with ADS-B (Automatic Dependent Surveillance–Broadcast) might not transmit during law enforcement operations due to specific operational protocols and regulations that may restrict the sharing of location data in sensitive or tactical situations. Law enforcement operations often involve confidentiality, security measures, and potentially operational advantages that necessitate limiting the transmission of real-time information, including the aircraft's position to ensure safety and strategic control during the mission.

The other scenarios, like maintenance checks or emergency situations, typically do not influence the functionality of ADS-B transmission in the same way. Maintenance checks would generally still allow for operational transmission unless specifically disabled for testing purposes. In emergency situations, transmitting information can be critical for ensuring safety and coordination with air traffic control and emergency responders, making the transmission of ADS-B data essential for those events. While flying over rural areas might present lower traffic density, it does not inherently inhibit ADS-B functionality; thus, the transmission would continue in those conditions.