I don't know a ton about this, and I don't plan on it since it's complicated as hell. From what I understand, though, leaving is a good idea. It's risky for sure, but the outcome shouldn't be that bad. From what I understand, the EU allowed travel from all countries within the EU without a passport or registration to that country. Also the currency was another issue, since there were other countries bringing down the value of the Euro. That to me seems like the main reason to leave - to let the UK stand on their own and not be brought down financially by other countries.