From reading other posts, it seems like electromagnetic induction is the greatest threat to electronic devices these days with either traditional HDDs or newer SSDs. Since current in a wire creates an electromagnetic field, I assume most electronic devices create their own field (albeit probably a weak one). Electromagnetic induction could be created by moving the devices around each other in a rapid fashion. Is there any danger to electronic devices (including their memory/storage and microchip functionality) when they are placed in close proimity to each other... say stacked on top of one another while operating?
Bonus Points: Assuming I was able to measure the electromagnetic field, what values would cause concern?