is it a fact?
It seems so,
not only unconfirmed change outputs
but any unconfirmed outputs. The developers are applying patches to make the opposite the default behavior as we speak, the patch is seven hours old.
The reference client will not allow spending unconfirmed outputs received from outside the wallet.
If I send you 1 BTC right now, the client will indicate you do not have sufficient funds to make a tx if you try to spend it before it confirms. Change outputs are handled differently though and could break transactions which use them before they are confirmed.