Maybe I am being cynical, or maybe I am just commenting on my experiences...
However, EVERY creationist that I have either known or encountered or read of on the Internet - including some of the 'professional' variety - that claimed to have been evolutionists lied about it.
They call it 'witnessing', I believe.
ICR geologist Steve Austin is a good example.
He claims that he was an evolutionist until he studied at Mt. St.Helens in 1980, when he baecame convinced of the truth of YESism.
Yet, he had been writing creationist articles under the (acronym) pen name Stuart Nevins for at least 4 years prior to that.
A student I knew in college was a YEC. Claimed to have been an evolutionist until he did some research on fish hearts.
As I got to know him better, I discovered that the closest he had ever been to being an evolutionist was a short period of teen rebellion... while he was at a private fundamentalist bible school...
And so it goes.
but that is just what I know...