I mean, I understand why this is a problem. However, I do not understand why you titled this post "Glad I stopped using Opera!" Opera Unite isn't mandatory, is it? If not then your title doesn't make much sense as Opera users are in no way compromised unless they specifically opt to run the server from their computers.
IMHO, I don't see Unite catching on though. In the US, uploads are heavily limited and PCs aren't left on all the time. Not to mention, serving content from a PC is against many ISPs TOS. I don't see the market for this.