From an IT standpoint, I think a single device obviously can't cause any issues. No single phone or sig al emitter could, unless specifically designed for it. Now the next I don't have as much confidence in, but I bet if even half or more use items, same deal. No big issue. If everyone at once decides or coincidentally all cause high emmisons, maybe that would be an issue.

However, how to you get everyone to understand that? You can't say most should do it, or ask half to do it. Too many would assume others should do it instead of themselves. Bystander effect etc. If you instead have attendants choose, how to be fair and not piss people off? If it really is a low chance but something you may possibly be sued for, also why do so?

Smartest thing for a large company to do is just ban it outright. It might only have a 5% chance of failure if and only if a passengers use their phones incessantly, and it would still be safer to just ban it outright.