Gavin, you COULD look at the previous owner of the coins and remove that address from your blacklist. However, I dunno about the IP data.
Yeah, I could, but it seemed like more trouble than it was worth; if you got coins from the Faucet into a non-empty wallet and then donated them back there's no guarantee that the donation back would be the SAME coins. I just don't want to deal with a lot of "I got five coins and then sent back ten but I still can't get more from the Faucet...."