Did they remain so after you hired them to research said laws? No one, lawyer, judge, LEO, or legislator can know every law that is applicable to every situation. The attorney knows the law generally and knows the law specifically in areas he/she has had reason to research.
A physician knows medicine generally and his/her specialty very well. A pharmacist knows medicines (plural) specifically, however a retail pharmacist will not know a medication that is not for public sale nor one that is used specifically in testing.
Blessings,
B
this reminds me of the time i went to debs gun range and they told me that the only way i could carry under the age of 21 was if i carried my parents "registered" gun. i later found out there was no gun registration in indiana.
One should be able to assume a gun shop owner (& FFL holder) would know the laws that governs his trade.. but sadly this is not the case.