The good news... and the bad news. It's a brave new world.
Advice? Always turn off or disconnect WiFi when not in use.
This would be a bigger problem for paparazzi, high profile event and red-carpet photographers I would say (Nikon D4 and Nikon WT-5A wireless remote maybe?).
This is becoming pretty scary. I can be watched on my computer, my smart TV with a webcam, my digital camera....nuts....
A $1 plastic lens cap will solve every one of these issues for unattended spying though any camera.