It's amusing that banana thinks Britain is some kind of dictatorship.

So "probable cause" is not a thing in the UK??
What do you think "reasonable grounds" means? It's basically British for "probable cause".

Here in the free world, you can tell a cop to fuck off.
Yeah well go out and try it. I mean literally tell him to fuck off, I don't mean be a bit of a dick. Go to your nearest copper and say "excuse me sir, but FUCK OFF", then come back to me and tell me you live in a freer place than I.

This woman didn't obstruct anything. She didn't interfere with paramedics doing their jobs.
Arguably she did, because she caused them to waste time, and caused them undue stress.

Causing outrage is not a crime, but if there's an otherwise insignificant crime that's been comitted, public outrage is motivation to persue charges, however petty it might seem. The CPS should only persue charges if it is in the public interest, it's basically their remit.

Maybe "arrest" means something different in the UK. Here, it means that the police have physically detained you. Your movements are restricted. Your freedoms are inhibited. You are being removed, physically, from the public because you have committed an act that defies law and order. For this to happen, the police need probable cause or a warrant.
Yep, here they need a warrant or "reasonable grounds for suspicion", such as a cop witnessing a crime, to give an obvious example.

It takes more than an 'accusation', and nothing about it is informal.
An arrest is a formal action, it's resorded and subject to strict rules, but it's not a formal accusation, because the police don't make formal accusations, the CPS do.

Yeah, but in America, before the police can ask you questions, they have to explicitly explain to you that you have the right to remain silent.
Yep, same here.

They exploit stupid people in interview, where remaining totally silent does not harm your defence, while making admissions does. I assume that's the same over there.