Hello matey,
The Schottky Diode isn't really necessary, I've got 3 now fitted to various cars and have had no problems.
I believe the main reason for fitting them is for radio interference problems and making the ESC run a little cooler. As I run 2.4Ghz radio and run Stock motors no higher than 10.5T Brushless the ESC etc run fine out of the box!
Hope this helps and any other problems then just drop me a line!
Dez