It's surprising how many people think the police are restricted in what they can do when making enquiries into whatever, be it a crime, road traffic offence, firearms licencing or anything else. Here's some I've come across:
1. "You can't talk to my little Johnny on the street because I wasn't there". Poppycock! Although interviewing him is different.
2. "You can't arrest my little billy because he's under age." Tosh. If your kid does naughty things, he can get arrested like anyone else. Just because he won't always be arrested doesn't mean he can't be.
3. "You can't enter my house without a warrant". Well there are circumstances where the police actually can lawfully y'know.
4. "I did nothing wrong, so you can't speak to me." Um, freedom of speech isn't chopped off when you become a cop.
5. "There's two referees for a firearm certificate so that means the cops or FEOs can't speak to anyone else about it". Yeah, righto. They might or might not. Might depend on how bolshy you are.
6. "Cops are there when I have a night out to keep me safe and should therefore give me a lift home". Partly right.
7. "You can't arrest me because you haven't got your hat/helmet on." Actually based on fact because there's some drink driving legislation that required an officer to be in uniform. But that won't get you off a drink drive charge these days.
And detectives seem to manage okay with most arrests they make. Wearing a trilby went out of fashion a while ago.
8. "I have never told a lie. Anything I say is the whole truth. How dare you question it." I think you'll find that cops are some of the most cynical members of society. And they get lied to so regularly to the extent that they can often tell. And being loud and pointedly continuing saying you are telling the truth just might have the opposite effect.
Of course there are checks and restrictions on some police enquiries. Without going into it too deeply, they include stuff like bugging and phone type stuff. That means they can only do it with the required permissions. But don't depend on it not happening if you are, for example a pusher (man). One modern way of ensuring you are pinched for something is to boast about it on Facebook (other platforms are available). Dumb offenders even today still do that thinking the cops won't look there.