you really don't think hfcs or thyme oil gets in your honey?
i've spoken one on one to several folks who have worked for large commercial migratory operations. they all say the same thing, bees are fed hfcs to make them brood up early, the hfcs gets stored in the comb and is extracted to make room for more brood, and to keep the hive size and weight small for shipping on a semi. of course this "honey" is worth more as honey than it costs for hfcs to feed the bees, so it is sold as honey.
if there were any desire to keep feed out of honey, it would be dyed before being fed so that it could be seen in the comb or the jar.
wrt thymol, i know one beekeeper that uses no treatments who loaned out some supers to another beekeeper, "organic" and "natural". the supers came back smelling strongly of thymol. there are good studies out there that show thymol residues in honey. to assume these things stay in the broodnest or disapate flys in the face of reality...and assuming that beekeepers don't feed or treat while collecting honey is like assuming that drivers on the road are sober and driving the speed limit.