Faced with this problem my first reaction would have been to simply make the battery diagram more legible and high contrast but this is a bit more elegant. Maybe there's a language barrier here too. Is the classic -/+ diagram widely understood around the world?
If +/- is idiomatic is an interesting question. But then, does it need to be? It's a matter of lining up the shapes on the device with the shapes on the battery. You don't need to know what the shapes mean, just what their relative position means.
Some people seem to be unable to get the batteries in the right way reliably. My wife (masters in a science from a top N university) has a significant failure rate on battery changing. Not having to worry about it would be better.
Maybe we could liken it to polarized plugs (for those of us in 110v AC land). We could have labeled plugs with + and -, and then told people to match them to the outlet when they plugged in a device, but over all, redesigning the equipment was more likely to work.
I think everyone should stop prefacing personal assessments of people by quoting their credentials first (MSc/PhD from a top X university), as I feel it should have absolutely no bearing on how intelligent one perceives them to be. I've met some seriously incompetent grad students, and they all seem to get their degrees in the end regardless.
