Wisdom shows few TRILLIONS euro for Bitcoin now, for Kraken.

Perhaps Wisdom should ignore results from obviously broken exchanges that show more then x100 times more, or less, then other exchanges (after applying possible USD/EUR/CNY conversions).

When selling in Great Britain, it seems there are plenty of shady replies, e.g. people

- do not send the requested paper written "I .... am buying Bitcoins from ....."
- do not send the requested photo / ID etc

even if the buying conditions clearly call for it. Instead they seem to

- send only some documents
- send very blurry impossible to read passport


What is going on with that?


Looking from other side, advanced traders, at least in UK, seem to all require a photo with all this at once:

- you
- your passport or such
- your credit card
- message saying that you buy BTC and that you know what you're doing

Why everyone require this, what scams happen in other case?

If the payment is national bank transfer, then a normal charge back (paypal style) should not be an issue, no?
Is this about stolen credit cards or what?

Even if, then is it responsibility of the seller of bitcoins to refund victim of credit card being stolen, or is this cost taken on by customer's bank or what happens?

Any common scams that can happen, or other tips how to avoid being scammed?