I have heard about gambling sites seized people's money when they are gambling from restricted countries but have you experienced this on any exchanges?
Well, I don't use a lot of exchanges. Maybe that is the reason why I don't have that kind of experience as well. But I believe this just happens when they smell some suspicious activity in our account. Perhaps it is very common in any exchanges, especially in reputable exchanges. It is a matter that they are also protecting against fraudulent activity, as most gambling sites are used to being a medium for money transfer.
If we have no other intention aside from trading. I'm certain we don't have to experience this other level of KYC.