It'd be up to you to be sure that you deleted any trace within your memory or hard drive of that private key. But if you could do that with certainty you should be able to 'import' your paper wallet momentarily, send BTC out to another of your addresses (or to someone who is expecting payment) and then delete it again. All without having to update all your backups.
This is HORRIBLE advice. Advice such as this almost guarantees that someone will permanently lose bitcoins. Please refrain from giving advice on how to secure your wealth when you ahve no idea what you are talking about. Some uneducated newbie might actually believe you!
Hmm I believe you're right given your num of posts... But could you explain your reasoning
When you send a transaction after importing your private key, the Bitcoin-Qt wallet will create a brand new address with a brand new private key that it doesn't tell you about. It will send the "change" from the transaction to this new address. Note, since this address is new, it is NOT part of your paper wallet. When you suggest to "be sure that you deleted any trace within your memory or hard drive", the typical user is going to delete the wallet.dat file that they imported the private key into. In doing so, they will have deleted this newly created private key and address. Since this new private key isn't part of their paper wallet, they will have permanently lost access to any bitcoins that will have been sent to this "change" address.
Thank you for this very Helpful post.
Just to be sure: If you load your private key into the qt and subsequently sent the amount to a new paper wallet, then it is safe to delete all data on your computer, right?
And one next question: if i load a private ket into the qt, sometimes the qt crashes. After re-opening the cq, the amount is however present. Now, I was wondering: what will happen if the amount does not get updated after such crash? Can is retry to load the private key, or are my coins lost in translation? Or, maybe in other words, as long as the coins are not spent, do they remain linked at the paper wallet address or are they sent to the main qt address?
Many thanks!