You are missing the part where they can transfer, and they can be on scholarship at the new school, but they can be blocked from playing in their first year if they are not released. There is speculation that NCAA may change this, but for now it is the rule.
That said, it is risky because it can be used against you in recruiting. "You know if you go there, and you decide to transfer Riley doesn't grant releases..." OU has the recruiting pull to get away with that with minimal risk, but most schools would not want to be known as that on the recruiting trail. I very much doubt West Virginia would block him.