Quoted from HighVoltage:
The cross-state-taxing laws aren't implemented everywhere yet... Technically, you're supposed to be on the honor system though.
The state taxes should really be in effect everywhere now. Read about the Wayfair case. If your company didn't charge sales tax for an out of state purchase, they probably should. The companies need to read the Wayfair case and find out about nexus. Lots of companies are going to be in for a rude awakening when it comes back to bite them in the ass. This was a Supreme Court case.