Please let me know.
Nothing is "left" anywhere. You pass it to us once, it gets loaded in a staking node, and the submission is deleted forever. Because of this, we can not recover private keys for anyone, should they become lost. You need to ensure that Private Key is backed up locally so you still have access to your funds. If you lose the Private Key and delete your local wallet before moving coins from that address, they will not be recoverable by us
That being said, you are free to pass the Private Key to me however you feel safest. You can email it to me, PM it to me here, pass it through IRC in our channel #MMXIV on Freenode; it's totally up to you. However you feel safest