RE: Lost Keys - A Comic
So in this case @moondancer762 the QR code WAS the private key. In a paper wallet there are 2 QR codes, the public and the private. Vault guy was examining his bitcoin paper wallets in a bank vault where there are security cameras and the security camera picked up on the private key side of his paper wallet.
BIP38 solves this by encrypting the private key with a password that you select, so anyone looking over your shoulder can't just snap it and steal the private key and hence the bitcoins.
Try it for yourself at either of these sites... https://www.bitaddress.org/
https://bitcoinpaperwallet.com/bitcoinpaperwallet/generate-wallet.html
You'll also need something to read it. I recommend mycelium for Android, then you just use "cold storage" import or spend.
OK, but even with a private key, one must know where to use it, right? I cannot just take that private key, plug it into my poloniex/bittrex/whatever wallet and receive the funds, right? Or does it work that way?
It works exactly that way.
Also if you think that's scary, consider that your private key is actually just a number between 0 and 2^256-1 which means anyone that guesses it also has access to your funds.
Fortunately that is still something on the order of a trillion keys for every atom in the known universe. So it's a really, really large space to search...