A major principal of our Common Law based legal system is, that if something is not expressly illegal, it is by default legal.
This being said, in this case there was no justified reasonable suspicion to permit the stop, determined after the fact, so without that, there could be no determination of probable cause, and no arrest. Thus anything found after the initial error should be inadmissible.
Which is why they (the elites) hate Common Law — they've been dismantling it for a long time now. Look how they've reduced the jury's power: nullification is virtually unheard of in the mainstream and presentments are practically verbotten.