How will they control and differentiate food flavoring to be used for food or eliquid? Ask the purchaser what they're going to use it in? They may have some control over ecig vendors because they'll be buying in bulk and the nature of their business is for ecig use; but, how about a diy'er? If they asked me, I would say I like to bake different flavor cupcakes.
EDIT: If they increase the tax on flavorings across the board, then they'll not only have ecig vendors/user up in arms but also bakeries.
I fully understand and frankly don't know how they'll differentiate. It would be easier for the hardware parts but with the PG, VG and flavorings, they'll almost have to get a list (perhaps from here ) as to who is using what for what. Just a decade ago, that would seem out of the question. Now... I'm not so sure.