Don't bet on it. If there is a wireless signal anywhere around it may be transmitting to it. I have a C-Pap that is only plugged into the wall for power and Sleep Number Bed that the only connections are to the wall outlet. Both of these pick wireless connections and transmitted data to a collection point. Your cameras may be doing the same.
AJ

My cameras are all hard-wired (no wireless), on shielded cable (coax) so i don't think there is any interaction between them and my wireless network unless it's happening either at the camera itself or at the DVR. But you just never know...