Cheating on Shipping Charges by an Address Change after Purchase?

[Billy]

Trying to figure this out....

Not sure how but I think that people have registered on my site with a USA address and purchased items. Then they go change their shipping address inside their account for another Country To Ship To. Because of this they are able to cheat me out of the correct shipping charges needed to ship the items correctly.

This is just speculation at the moment. I haven't been able to test this theory yet either. One thing is for-sure people are getting charged USA shipping rates for other countries.

I have looked all through the address part of the system. It does not seem to track the users habits/stats about the use of the address/shipping part of the website. If the BO tracked the different addresses used by the clients I could put this theory to bed.

Maybe I have something checked wrong in my shipping...

I just don't know how they are doing this!

Thanks for any of your time in advance

Billy