From what I’ve read, the state of Maine was actually issuing subpoenas against the billing records of various well-known online cigarette sellers, and cross-checking for Maine addresses.
No suprise here. The State actually hired some people to work in Augusta whose jobs are to read through swap, sell trade newspapers (such as Uncle Henry's) and classifieds taking notes on big costly items. They are watching Mainers like a hawk making sure everybody pays taxes on whatever they sell in classifieds.