The tailgate stop and search was not done incorrectly. Read the story. The suspect gave consent. Give no consent IF you have something to hide and yes that may be RS if an LEO can articulate the facts.
What can an LEO do if they want to search is governed by the 4th amendment. No search can be done on your person with a REP. Leave a window open no REP. Only way an LEO may search is with consent, search warrant, exigent circumstance, mobile conveyance (limited). Any search an LEO would need to articulate PC.
What gets confusing is a terry stop. Under a terry stop an LEO may temporarily detain an individual with RS that criminal activity has been, is or will be afoot as well as BOLO, etc. then an officer may detain you with reasonable force including an external pat down for weapons and if during a pat down an officer finds what he believes and can articulate as contraband then it becomes an SIA.
They cannot circumvent the fourth amendment if they do then all subsequent evidence would be thrown out from the fruit of the poisonous tree doctrine which didn't hold in the other case since, again, the news article stated the suspect gave consent.
I would beg to differ with you analysis. Since the stop was improper (NC law says only one tail light is needed) anything that happened afterwards was technically fruit of the poisonous tree. Without the PC (none existed) the stop would not have been made. Granted the suspect messed up by consenting to the search, but that is another matter.
The larger issue is, again, that there is now a double standard for LE and citizens in terms of being responsible to "know the law."
Your explanation of the Terry Law is also a bit off. Yes, an officer may temporarily detain you if he believes there has been, or about to be a crime to investigate that crime. But that does not grant carte blanc to do a pat down. The officer, in addition to having RAS of the aforementioned crime must ALSO have RAS that a subject is armed. While is is a fine line to tread, LE treat everyone, everytime as they are armed so therefore that has become their de facto RAS for the pat down. Not exactly the letter of the law but a clear example of how rights are incrementally chipped away and how acceptance of seemingly minor infringements can be, over time, accepted as normal practice.
From the Terry v. Ohio ruling"
Our evaluation of the proper balance that has to be struck in this type of case leads us to conclude that there must be a narrowly drawn authority to permit a reasonable search for weapons for the protection of the police officer, where he has reason to believe that he is dealing with an armed and dangerous individual, regardless of whether he has probable cause to arrest the individual for a crime. The officer need not be absolutely certain that the individual is armed; the issue is whether a reasonably prudent man, in the circumstances, would be warranted in the belief that his safety or that of others was in danger. Cf. Beck v. Ohio, 379 U.S. 89, 91 (1964); Brinegar v. United States, 338 U.S. 160, 174-176 (1949); Stacey v. Emery, 97 U.S. 642, 645 (1878). [n23] And in determining whether the officer acted reasonably in such circumstances, due weight must be given not to his inchoate and unparticularized suspicion or "hunch," but to the specific reasonable inferences which he is entitled to draw from the facts in light of his experience. Cf. Brinegar v. United States supra.