I have a similar experience.

First time my parents were rejected because they said the truth that both I and my brother are in US. Second time I thought to not mention my brother at all, if visa officer askes, I told my parents to say that my brother is working in China, they even got a "job certificate" for my brother. We know cheating is bad and risky, but there is no way for them. They took a long trip to Beijing, if they got rejected again just because they saying the truth again, this will be a very sad thing. So we took the risk and we succeeded.

The only diffence is that I am the appliant for both time. I don't if the VO has detail record for the first time. But we decide to take the risk anyway.

Hope this helps. But again there IS a risk such as if they find you cheating your parents may lose the chance to go to US forever or some bad thing like that.