I had a complaint from an elderly customer when I was a 19 year old tv repair man. He had one of the original Philips G11 teletext tellies, it was changing channels and Ceefax was coming on at random.
I went through processes of elimination like changing his remote handset and receiver panel etc, I even brought it in to the workshop for soak test and nothing. However one day I visited this customer and caught it changing channel at random, it seemed to change when his budgie chirped, I told the customer that his budgie was chirping on the same frequency as his remote handset.
After looking at me like I had two heads he said “you young-uns think I’m a silly old fool, if you think I’m going to fall for that one you’ve got another thing coming!”. I obtained a Philips teletext set that looked almost identical to his set but used an infra red remote. I replaced his set with this one and put his set elsewhere, this was the end of the problem and I had a satisfied customer even though he still didn’t believe the budgie story.