Also, it has been very clearly established that the police do have a requirement to inform you of your rights under some circumstances (Miranda).
At the risk of disclosing too much info...
I wasn't mirandized when I was arrested (minor drug charge at 18, was dismissed, and I don't use drugs) for, essentially, hanging out with the wrong crowd.
My lawyer told me that if it had been a couple years earlier, the case would have been dismissed since I wasn't read Miranda.
In NC, to my knowledge, whether the accused is mirandized or not ends up being a factor
in court if he or she incriminates himself or herself during the arrest or detainment, but does not result in a
de facto dismissal (any more). I'm sure it's also dealt with on an administrative level if it is a frequent occurrence.
As for the search thing, think again. There are tons of stories about cops saying "I'm going to search your car." They do not say "You are required to let me search your car," but they certainly do not say "You have a right to refuse this search."
It is possible that a good lawyer would get the case dismissed in this instance, but that is not the norm...