I do know that there are jurisdictions in which police officers can ask for ID for no apparent reason (here in Italy they can just ask a person for ID without any reason or any legit ground, just for formality), and there are jurisdictions wherein it is illegal to do so (seemingly the UK, but correct me if I'm wrong). For the cases in which asking ID with no ground is illegal, it seems that the definition of "ground" changes according to any police officer, because any police officer can bypass all this thing and just say "I checked your ID because you look like a drug dealer", by making it pass as a legit ground while it is not.
Is it correct to say that the laws stating checking without grounds is illegal, pragmatically, are just rendered meaningless by how any officer perceives the notion of "ground" or can samely make up a new one? As I said, if a cop checks illegally a person without any ground, they can just say that they suspected the checked individual to be a drug dealer and get away with it.
So as I see it, I can say that these laws are circumventable with any excuse that a officer may give, and the latter can be undisputed and unverifiable, since (fake) suspicion is not verifiable.