Amazon is pushing credibility to the limits in the USA. According to the Wall Street Journal, as quoted on the Tax Prof blog:
As an online retailer, Amazon can avoid collecting sales tax in states where it has no presence, at least until Congress changes the law. But in states where a company has actual facilities, such as warehouses, states tax officials can require the company to collect sales tax.
Despite operating hundreds of thousands of square feet of distribution facilities in the eight states, Amazon says it doesn't have any presence in them. The company argues that it doesn't operate the plants, its wholly owned subsidiaries do. ...
I can only guess they think that the States are stupid, or we are.
Rumour has it that Texas might take them to the cleaners. I hope so.