In the past, police officers have been allowed to frisk you for no reason. But solely to check for weapons. Anything found that could NOT 'reasonably' be considered a weapon would be inadmissible in court. Usually, generally, kinda sorta. Govt did not like that they couldn't shake folks down when and where they please.
This isn't a huge loss of freedom, because it relies on the victim being guilty of some minor or tiny infraction before officers can get away with illegally (note, admittedly and expressly illegal under the Constitution) searching folks. So, they shake you down, run your ID, and if you have some tiny unpaid parking fine anywhere their database can reach, anything ELSE they find on you is now admissible because "costs of exclusion outweigh its deterrent benefits".
Justice Sotomayor actually put forth a pretty good pro-Constitution dissent.
