Take the appropriate action and verify that the warning light turns off.

Taking Action
Message Indicated on DisplayMazda 6 Owners Manual: Advanced Keyless Entry System
WARNING
Radio waves from the key may affect medical devices such as pacemakers:
Before using the key near people who use medical devices, ask the medical device
manufacturer or your physician if radio waves from the key will affect the device.
The advanced keyless function allows you to lock/u ...
Mazda 6 Owners Manual: Child-Restraint Precautions
Mazda strongly urges the use of child-restraint systems for children small enough
to use them.
You are required by law to use a child-restraint system for children in the U.S.
and Canada. Check your local and state or provincial laws for specific requirements
regarding the safety of children ...