Ok, I was at work today, when a customer that I have never seen before (we have LOTS of regulars) is lurking by the DVD's. I go ask if there is anything I can to to help him, and he asks if we can get pre-owned VHS movies.
I politely told him that VHS movies were quickly being phased out for DVD's and that they were about the same price. He then tells me that he will never own a DVD player because they can be made to send out ultrasound waves to disrupt brain synapses.
Almost too stunned to say anything, I blurt out "that's impossible!". I then go through about 10 minutes of LASER technology and explain to him that adding ultrasound to the light waves in the laser beam is not possible.
I then start to play a little and tell him that is biggest danger is a wide burst of ultrasound waves in a public place. His eyes widened, and he asked me how would he stop that from affecting him.
I told him that using a white noise generator or a device to cancel out the ultrasound waves. We talk for ten more minutes on where he can get the stuff to build a Walkman sized unit to wear all the time.
The last thing I told him as he walked away is too NEVER buy this stuff with anything but cash, cause all the items are being tracked by various governmental agencies.
His last words to me were "good thinking!". He left, and it took me almost 20 minutes to regain enough composure to go back to work and tell all my co-workers what had happened. I think we need to start stocking Tin Foil!