I know this is a little bit of a side track, but....
I had a bit of a debacle with some HiTec receiver wiring instructions just the other day. The wiring diagram was black and white and no "+ -" were anywhere on the page. I assumed that black on the diagram indicated the black (-) wires, BUT I WAS WRONG
... Black on the diagram actually indicated "hot"(+) which in the case of our RC gear, is red.
This was quite confusing and the receiver was damaged because of it....Hitec is taking care of me, but a simple "+ -" somewhere in the instructions would have been too easy and saved everyone a lot of hassle.
It's always something in this hobby