Therein lies the 64k BTC question....
Culprits:
1) Bitcoin7
2) The user in question screwing around who had his own referral code linked. (I give this one high probability).
3) College kid pranskter (maybe high school in all fairness).
4) Competitor exchange trying to discredit them....
I'm sure there's more but #2 is high on my list.
Thanks. If it's 2, 3 or 4, I'd be more inclined to give bitcoin7 the benefit of the doubt. Not knowing, I'm very wary.