Shipping validation conditions does not check shipping state

I am trying to restrict selling certain products to a certain state. The plugin works – thank-you – however I have found a loophole.

It seems that the shipping validation conditions checks the billing state, not the shipping state.

Lets say I am trying to stop selling products to the state of Alpha. If I have the billing and shipping state set to Alpha in both, your plugin works and the block occurs. If a determined customer tries to get around this and sets their shipping state to, say, the state of Bravo whilst leaving their billing state as Alpha (and all their other address details the same), the sale proceeds.

You may wonder who would do this, but I have experienced numerous times when a determined overseas customer has forced-through transactions using incorrect details just to make it happen, including Americans using non-US states – and no US references on the site at all! – and putting the state after the suburb before it.