I'm running 2x Apollo, 1x iPower, and 4x Welthink 315 cmh. While 2 welthink, 1 apollo, and the ipower were all running I ran a few RFI tests. I tried running 560 AM to listen to static, since nothing is broadcast in my area on that frequency, it was constant static, driving up and down the street the static changed/increased as you passed obstructions (houses or giant oak trees) on the east side of the road. Static also went through the roof as I approached high voltage power lines. My house is one of those obstructions where you hear static increase, but no different than any of the other obstructions. I tried again on the nearest AM station I could receive (I believe it was 600 AM.) With an actual station coming in, I only noticed interference from the high voltage power lines, none from the trees or houses, including mine.
After playing around with my phone, radio, laptop, ... I conclude that my mylar causes some minor issues, cell phone signal drops, wifi loses strength, ... But it make no difference if lights are on or off.
Reason I think most manufacturers fixed the issue is that complaints are way down and usage of devices it would interfere with are way up over the last 5 years. The complaints are so rare now, and usually fixed by a replacement. That indicates that they changed something to fix the issue.