The laws against "structuring" aren't old, they are a War on Drugs innovation begun in the 1980s that become more and more complicated year by year.
Monitoring your handling of cash to catch you in some other crime is certainly a Fourth Amendment violation, and it does create an environment where they can make "any damn thing they want to be a crime"-but it's new, not old, and we can change it if we want to.
Yes, an innovation developed by the henchmen of that grand old conservative, free marketeer, defender of the constitution and individual rights Ronald Reagan. Your excellent point sheds light on the fact that there probably hasn't been a conservative politician who believed in a truly free republic since Robert Taft:
Taft in 1950:
"We have over the past 20 years, in the interests of 'national security,' laid the foundations of the emerging American police state, where there is no liberty, no privacy and no peace. Persecution of dissenters of any kind will soon be as routine as egg and milk deliveries. No one will question the dictates of Washington. By winning the war against fascism, we have become the fascists and will probably lead the world into a horrfiying catastrophe from which few will live to tell the sad tale."
(I don't think Goldwater would qualify as an example of a conservative politician who truly believed in a free republic either given that he seemed as just as scared of the commies as the rest of them--or more--and, therefore, just as willing to destroy the constitution for the sake of "security.")