Can they charge you with anything and how could they find out

They could find out by other people giving contradicting details.

Isn't this obstruction of justice?

Yeah, I lied to a cop telling him I was staying over at my mates house when I was out past curfew, they called my mom and she told them otherwise of course. Got charged with Obstruction of Justice and Curfew.

I mean giving false names, address, number etc when pigs turn up to a scene and start asking questions. What would the risks be if a person was to do this

Obstruction of Justice
Concealing Identity (can be a felony)

It really changes depending on where you live.

Could someone simply not answer any questions whatsoever if not under arrest? I suppose this would end with a night in the cells and not be worth it

You dont have to say anything. Right to remain silent remember? Make them find out. Make them take you downtown and get you identified. They get paid for this after all.

Officer, do you mind if I look at your warrant as I call my lawyer?

^hehe didnt think of that. You cant even be taken downtown unless they have a reason. And they ave to have proof to have a reason to do it. If you get caught speeding and there no photo/video then they cant fine you.

I suppose it depends whether the situation is worth it. Nothing wrong with giving your true details and then leaving if they have nothing on you and you don't want to go downtown I suppose. Unless you are trying to not be on record at all.

Thanks guys