i think here in Canada, retail consummers must pay additional $ GST 6% plus duty $$ on imported t-shirts made in USA. With all the computers/databases etc. at point of entry its getting to be a bigger issue then in the past.
I think it might depend on the value of the shipment.
For most retail orders like brownturtle would be sending (under $20 value), there are usually no GST/duties to be paid.
I may be wrong, but dont peeps like spreadshirt.com have zone-production ?
Spreadshirt actually started in Europe, so their intitial production facility is there.
They also run off a different business model than a single retail shop. They process orders from 1000's of companies that sell through their service.
They just recently opened a production facility in the US, but it makes more sense (economically) to do this for a site that processes 1000's of orders to the US and 1000's of orders to the European markets for 1000's of different sellers than it would for a smaller company that has just their own t-shirt line selling a few different designs and not selling at that volume.