Here's what the prohibitionists keep avoiding with regard to the "broccoli vs cauliflower," "we can't tell them apart!" appearance issue of industrial hemp: it's crap. They must be high.
If you want to grow quality hemp, then your plants will be tall stalks with tiny flowers and therefore very low THC -- ideally all stalk/no bud. If you're growing pot, they'll be squat plants with large flowers and (presumably) high THC -- ideally all bud/no stalk (and let's not lose sight of the unavoidable fact that THC levels have increased directly due to the "War on People Who Use (Some) Drugs"™, for the same reason that higher-alcohol-content liquor became the bootlegger's product of choice: more bang in a smaller, more easily handled and concealable and transportable package). Anyone intent on entering either market has a considerable economic vested interest in maximizing the preferred characteristic exclusively, because the non-preferred characteristic detracts from the preferred characteristic.
The objectives of the two crops are very different. The plant-spacing of the two crops are very different. And if you were to cross-breed them (as would unavoidably happen if you tried to hide one amongst the other) in an attempt to circumvent arbitrary THC level restrictions (and also presumably attempt to split the difference in spacing requirements, as well, in your attempt to deceive), then your crop would be market-competitive -- and therefore profitable -- neither in the hemp market nor in the pot market. Your product would be rejected by your intended customers. Marketable THC and marketable fiber are incompatible and mutually exclusive -- indeed, mutually destructive. For a profitable crop, you need to pick one and actively avoid the other. The autocrats have made no attempt to debate these points. Why might that be?
Even most cops ought to be trainable to tell the difference. And even government used to understand.
Seriously. Why the hell are we still talking about this...?
Anyway, herewith, the NH Senate Judiciary Committee hearing on HB1615, "relative to industrial hemp," 4/19/2012. In toto -- it simply wasn't worth my time to excise the lone tripping opponent. (The House hearing can be found here, their Executive Session here.)