I'd like to know how they can try to collect taxes when 99% of all e-cig/PV mfrs are in China.
This is why you always see the 'xx% of wholesale' term. Do you remember those little stamps on your pack of cigarettes? Retails don't pay/file the tax. They are required to purchase their supplies from a licensed distributor. The distributor pays the tax, places the stamps on, and the cost of the tax is then included in the price right down the line. Retail stores are then fined if they are caught selling the product without the stamps on them.
This is one of my concerns about taxing e-liquids. The stores will have no real say in what products they carry. They will only be able to carry what their distributors decide to carry.