Online casinos have to be registered to be legitimate, and the casinos have to have a license that is going to help them be sure that they are operating in the right way. People who are registering for an online casino have to say what country they are from because these casinos only operate in certain countries. The casinos have to get licenses from each country to operate, and they cannot allow people from certain countries to play. The site typically tells the player if they have been trying to sign in from the right country. This could lead to people being locked out of the casino. Someone who tries to use some sort of proxy service might get into the casino, but they will have a problem at the end of the year when the casino tries to send them a tax form. The casinos are hoping that everyone will be honest so that they can run their businesses in the right way.