I hear ya Erik, and did on my last two, the G and the IV, even though they were more expensive. I buy all my parts from them over Jason, regardless or the cost.
With the
JS-2, the price difference was nearly $300 (the original AAF price was over $1000 plus shipping) and unfortunately that's more than I can afford to ease my conscience.
As far as grey market, I've never been asked by Tamiya for proof of purchase. If I send a MFU from my Tiger, they can't know whether I bought it as a FO kit or a stand alone part from Jason, AAF or Banzai.
They won't honor stuff sent to them from outside the US.