Pending stakes become “Active” status once the deposit is made. At this point, closing the stake before it reaches “Mature” status will incur a penalty. The maximum penalty would occur if the user cashes out during the same epoch of the deposit (100% penalty). For that reason, the "Withdraw" button is disabled during the first epoch the user enters the pool. The penalty slope is a straight line downward, meaning the longer the stake runs, the less the penalty is, should the user need to break the stake. Example: if the user cashes out 50% of the way through the term of the stake, the penalty would be roughly 50% of the principal originally deposited. It is important to plan properly and to only stake for a period which you are willing to stay vested.