It looks like it's enforced primarily against businesses, which probably are pretty good at paying the tax: https://www.salestaxinstitute.com/sales_tax_faqs/i-b

It looks like it's enforced primarily against businesses, which probably are pretty good at paying the tax: https://www.salestaxinstitute.com/sales_tax_faqs/i-bought-a-taxable-item-and-the-seller-didnt-charge-sales-tax-do-i-have-to-pay-the-tax-anyway https://www.salestaxinstitute.com/sales_tax_faqs/i-bought-a-... For consumers and very small businesses it also looks like there are often exemption thresholds which make paying it a legal requirement something that a typical consumer who buys out of state will not run in to.