Why has my son's remote control car got a mind of it's own?

My son’s first remote control car works not only with the controller but allso the tv remote too… which a good frined explained to me was because they probably work off the same infrared signal.

However, it also works…(and when i say works…i mean its wheels start going round and the lights flash on top and it makes noises….) when i switch the house lights on and off…. is this just electrical surges?? Alll seems a bit odd to me….