my 2 p worth
People with koi ponds use them, some say they are marvelous some say they are rubbish, personaly i think its physcologial, its a gadget so you will look for things that have happend for "no reason" there probably is a reason, but becuse of the new gadget it must be that.
Are you sure its radio? you can transnit legaly without a licence, since these things are so feeble, and probably on a non licence required frequency* they are ok to use if you really want one, i saw one today, it had a nice sequence of lights, seemed an expensive set of lights to me
*"walkie-talkies, radio remote control toys do not need a licence, if these things did they would cost more