It is very common to find safrole free sassafras oil and extracts. It is not a ploy in order to fool the clandestine chemist, as it would be fairly easy to disprove them. And if a company is selling safrole free extract that contains safrole that could be a huge legal issue.
I assume oils for use in food products should be safrole free. I say this because I beleive there is a limit to safrole content in food products, safrole was banned from food products in the early sixties, however there must be a maximum allowable limit, as it would be impossible to have zero detectable safrole in said product IMO. I always wondered if they just use low safrole containing extracts or if they actually separate the safrole containing fraction. If that were the case I wonder what happens to all of the safrole. I think I just found a new business venture, (methyl_ethyl's safrole collection agency, "we pick up and dispose of your safrole for free We must be crazy!!!!!! our loss is your gain".....)
Just kidding I think they may chemically treat the starting material ie. rootbark, leaves, branches, what have you. I am not sure what the exact process is, however I doubt they fractionally distill it, although I could be wrong.
good_luck
methyl_ethyl