I had a look at some non-KYC exchanges such as localbitcoin. Was surprised to find that the premium over spot is around 10-30%.
Localbitcoins is a kyc exchange
1) What is the reason for such a high premium?
For example, if the central Bank of a country ban Bitcoin, it can lead to it. What can make people to panic about Fiat can result to Bitcoin premium price in a country, like war.
2) Are there people who buy from KYC exchanges at spot price and then sell at non-KYC exchanges? Or are KYC-exchange bitcoins "tainted" and not allowed to be sold there?
I am not into arbitrage, but this is what I experienced even Nigeria Central Bank ban cryptocurrencies. When the price of bitcoin was at $35000 or around that price, I saw it at a price of $50000 or above on some exchanges, but I was not able to sell cryptocurrencies again on the exchanges, but it was all over the news that Bitcoin was selling in Nigeria at premium price. On all exchanges that it can be traded p2p, the price was and is still now normal bitcoin price, even if it seem high to you, you will notice it is still normal price after you end up trading the bitcoin to Fiat.
Know that Bitcoin is not selling at premium price on no-kyc exchanges, if the price on the p2p increased on kyc exchanges, expect the price to have increased on no kyc exchanges as well.