this won't work on 2016+ not sure for previous years, if the key is nearby or even in the car; the trunk request button will allow any stranger to press the request button and open the trunk.
try it now, you don't even need to press the unlock button, as long as the key is near the trunk, you don't even need to take the key out of your pocket , just press the request button above the license plate under the trunk Mazda logo and the trunk opens up while all the doors remain locked,
once the key moves away from the trunk the request button won't open the trunk, you don't even need to press the lock button when you walk away after you close the trunk, the request button deactivates once the key is out of range.