Well the plan was to split the 8 bitcoins up and send them to a number of smaller paper wallets when I received them but they were gone before I had the chance. 
I'm assuming for now that guiminer-scrypt is just a false positive so I still have no idea how this has actually happened.
I'm assuming for now that guiminer-scrypt is just a false positive so I still have no idea how this has actually happened.
Yes, all Bitcoin mining softwares are detected by AV's. At least they warn you about it. It's expected.
Is that wallet a new one, created by Bitcoin-qt? Have you ever added private keys to it, private keys that you took from someplace and forgot to label them as such and now you used that address to get those coins?
If this is true, someone should report this to moderators and warn other people
What can the moderators do? As for warning other people, well, you have this thread. But I'm not quite sure what you want to warn them about. He received Bitcoins at one address and they were sent out of that address 1 hour later or so, maybe when the other person who owns the same address private key noticed he had 8 BTC more than supposed.