Just to clarify, the coin flip technique as I understand it works something like this.
You assign heads to A, tails to B, then flip the coin. While it is in the air, you realize you are rooting for heads or tails. What then happens with the coin is immaterial, you have your answer. The variation above involved waiting to see how you felt about the result, but I understood it to be the same thing–what matters is how you feel, not the actual coin result.