The rules are entirely arbitrary, and have no basis in science. I have been told to turn off a GPS receiver that ran on two AA batteries for 12 hours. There is no possible way that you could affect the planes electronics with the power of two AA batteries. Especially not with electronics designed to be quiet enough not to interfere with the extremely weak GPS signals it must listen to. The electronics on a plane must be horribly designed if they can be affected by any hand held electronic device.
In California, any time I have seen an Amtrack train going the same direction as me on the freeway, I was passing it, never the other way around.