Another bug with group prices

[ktsixit]

Hi,
I just discovered a new issue for this extension.

Let's say that a customer signs up in my website. He's not activated yet but he's trying to make an order.
When he makes an order, using the same email that he used to create an account, the group prices are listed in his order.
Although he's not activated he grands access to group prices.

Could you please fix this?