Usually closed beta is done by invitation only. Hence the name "Closed" beta. It is common for a game publisher to do a wipe between Closed beta and open beta to keep things fair to those that were not invited to play during the closed beta period. PlayWithI decided to allow Public Access during their CBT. And they have assured us all over & over that they will not wipe our game data.
Once the game publisher allows open public access (the "Open" in Open beta test phase) they would be in very serious trouble if they wiped the game at any time while in this open state. You will never see a wipe going from open beta to release. Usually because people would have made donations and purchased ingame goods during that period. Wipe from OBT -> Release = Game Death because players would no longer trust the game publisher to protect their accounts.