It will depend. One of the most valuable diagnostic tools, as border staff will tell you, is to just go be interested in people. So maybe a BTP Officer (British Transport Police) will go ask them why they're taking photos of CCTV Cameras in a railway station or other critical infrastructure.

As constables they're entitled to ask who you are, and what you're up to. They can write it up and it goes into the enormous pile of puzzle pieces for intelligence analysis.

"Taking photos of cameras at major train station" + "Purchased a truck full of fertilizer" + "Attended talk by nutjob entitled 'War to save the white race'" is three completely legal things that add up to let's authorize detailed surveillance because this is a possible terrorist.

Whereas "Taking photos of cameras at major train station" + "Attended Extinction Rebellion March holding banners that said Eat The Rich" + "Wrote angry letter to local politician saying that they'd be judged in their next life for refusing permission for a new vegan bakery" is three other legal things that add up to this is probably just a hippy and we should keep paying attention but there's no immediate threat.

In this context, it means "satisfactorily dealt with" and is a common (UK at least) English saying.

Here it is obviously used to fit into the rhythmic context to make the instructions easier to remember.

"Sorted" is a word used here to mean that a task has been completed. e.g. "Did you get that thing sorted yet?" "yeah, I sorted it out last week." It can apply to basically anything. You might also simply say "Sorted." as you finish doing whatever it is you're doing, to announce that you are finished. Similar to just saying "Done." or "Finished." in this respect, possibly with the added implication that there was a problem that has now been solved.

It means "Your task is now complete, docile citizen. You may continue with your day."

It's a slang term.

Others have mentioned some meanings, but you could also say something like 'yeah, she's sorted' (meaning, she's a good friend).

Or generically something like "That's sorted, that is", meaning good.

Well sorted, innit m8.

'sorted' doesn't usually imply anything bad. It's rather like '[we've] got this covered'.