Back in 2009, Eskom (Our Power Co in South Africa) Decided to Implement smart meters in Blairgowrie.
Unfortunately there was a bug in their code. Something transmitted a signal on the same frequency that the meters communicated on, and they did not understand the signal, so they sent replies, and then other meters got confused.
Eventually you had thousands of meters in a town all transmitting something on 433mhz, jamming most Car/Gate/Alarm remote controls.
Even worse, now and then the signals were interpereted as a valid transmittion by the remote control receivers, and peoples gates/cars/etc were opening by themselves.
IIRC it took them a long time to figure out where the problem was (imagine ICASA trying to Triangulate in that mess), and then fix it.
At least the battery companies made a killing on remote control batteries
-----
During May 2009 the neighbourhood of Blairgowrie, set just north of Delta Park and next door to Linden, Robindale, Craighall and Bordeaux, all woke to discover that their remotes no longer opened things like cars and gates. Which can prove a little vexing when you need both in order to function at all in Johannesburg. For well over a day technicians roamed the streets in search of the cause, whilst most of the suburb invested in new batteries that did not help at all.
After much debate and various outlandish theories that affected no fewer than 4 000 households, the remote saga was touted as a signal jamming problem. The cause: a small business was broadcasting a data signal that interfered with the city's newly-installed smart meters, installed to give them control over people's geysers.