I used to fly but don't have a commercial license. I do have decades of electronic experience (including avionics interfacing and FCC computer interference approvals... you'd be amazed what cables can pick up), and have read all the NASA airline pilot electronic reports.
I'm sure that your family members have not had a bad experience, and that's great. Good for them and I hope it's always that way. (Do they have electronic engineering experience?)
Meanwhile, other pilots have filed reports where autopilots have disengaged, navigation instruments have acted up, and TCAS alerts have shown up as being right off the tail (zero distance)... possibly due to a passenger device being in a row over the antenna cable running through the fuselage... causing the pilots to take unnecessary evasive measures.
I think that, due to both luck and skill, passenger electronic interference has not been a deadly problem. Heck, it might even be rare these days. But you know what? Some of the worst airliner accidents have come from miscommunications and/or a distracted crew. In flying, there's never a good reason to tempt fate just because you can.
More importantly, decisions like this should not be left up to the airlines themselves. Historically, they have always chosen the cheapest method of doing something. That's why I'd like the manufacturer themselves to certify each plane type.
(Last year, Boeing was doing just that, certifying a WiFi installation on some 737 models. That's when they accidentally found that a runaway power glitch on a test device ramped up the WiFi output enough to cause the pilots' display panels to blank out. Not something you'd want while landing in the rain at night, that's for sure. So why keep WiFi on, and tempt fate? As you get older, you learn that it's always better to be safe than sorry.)
