I don't think there are specific written rules for many countries. One hyperactive Romanian border officer requested me (in a threatening tone) to remove all th

I don't think there are specific written rules for many countries. One hyperactive Romanian border officer requested me (in a threatening tone) to remove all the "large electronic equipment" from my backpack - even my SLR camera and all the lenses. This never happened in ~10 other countries where I traveled with the same backpack and contents.