It might be that you bought items with cash, or tnt believes you did, and they might think you're a stolen middleman/storage account for the items or pets. Another thing that might have done it if you are moving ips a lot, or using vpns a lot they might think more than one person has access. A friend maybe 4 months back got cookie grabbed though, maybe you were too, and it was accessed while you were gone or when you weren't aware of it? He was frozen for his protection too. I recommend staying away from user shops unless its critical to get said item, especially if the item is easy to sell like a codestone, paint brush or lab map piece. Something you can do to protect against cookie grabs is logging off often.
