Says who?
Cause that's exactly how it works....... Cannabis oil that contains no THC is legal in all 50 states.
It's been on the market forever.
From that angle, seizing cannabis oil alone is no substantial proof in court. To be that, the THC content of the oil has to be determined in a lab. If there isn't any, then there's no recreational drug at hand, instead just some herbal oil used for all kinds of stuff.