However, I do know that in my own wallet, several unlabelled addresses
have appeared over time without me requesting for them to be created.
Could you provide a bit more clarity on where these addresses have appeared? In Wallet.dat after using PyWallet or in the receive coins gui?
Bitcoin-Qt uses a regenerating key pool of a 100 pregenerated keys mechanism to handle change
and to read Satoshi's words:
Are these be the change addresses used when I spend bitcoins, or are
the change addresses invisible from the GUI?
My understanding is that all change addresses should be invisible in the normal GUI. The only way you should be able to see them is if you open wallet.dat.
I hope this helps.
I spoke with Wladimir here is his reponse:
That indeed sounds weird.
The old UI (wxbitcoin) used to generate new, unlabaled addresses in
some circumstances. With Bitcoin-Qt this should not be happening.
The wallet starts with one receiving address, and all receiving
addresses after that should be manually created. If receiving
addresses still appear out of the blue with 0.8.x this is a (minor)
bug. To be able to fix it I need a way to reproduce it.
Could you take some screenshots and also forward me your hardware configuration. I'll send it to him and hopefully we can try to reproduce it on his end.