As noted in the post, I believe Amazon has some extra anti-fraud stuff going on. I actually went through the purchase flow sans password as I was writing the p

As noted in the post, I believe Amazon has some extra anti-fraud stuff going on. I actually went through the purchase flow sans password as I was writing the post, so it certainly is possible. However, other times I have gone through the checkout flow and have been prompted for a password. They clearly value security/privacy over convenience for other aspects of the site (past orders, etc).