^ I had a sort of thing that I did similar to what you said about turning off the sound and looking away. Whenever I got the Gameboy Advance SP I would close it and turn off the sound because I was afraid that I wouldn't catch the Pokemon. I never did anything like that with the gameboy color or...
Surprisingly, I have never heard of this, despite being the big Pokemon nerd that I am. It's just a myth of course, though. No gimmicks that can help you catch Pokemon... just a giant equation.