This is why libertarian constitution is designed to be simple and objective, as much as possible. Corruption can happen anywhere but libertarian governments would be among the last to have it. The philosophy also happen to rely on technology to enforce the constitution which rules out subjectiveness/corruption considerably.
Also though there are many variations in libertarianism but none of it will interfere between two consenting adults (such as buying drugs etc). Thus no wars on drugs.
which, as pointed out, is completely hypothetical and additionally defies common sense. burden is on libertarians to prove this extraordinary claim. unfortunately, most non-libertarians don't know/care enough about the whole issue to even demand such proof which is why we are stuck with all this "soft" libertarianism roaming about causing great damage.
Note: "jailtime += 20yrs if skin_color==black" is objective but not libertarian.
In libertarian land, mass protests against police corruption and abuse occur, the media is not allowed to enter, the protestors are all shot on sight. The end. The burden is on libertarians to explain exactly why this would not happen in the absense of any democratically elected government.