2 of the Paris attackers can via the current migrant routes.
Most of the weapons came from eastern Europe, driven straight across with no borders to concern the traffickers except with the outside chance of getting caught by traffic police.
Interesting article on this here[/url].
Sadly, the actual issue of staying in or out of the EU and all the related matters that should be discussed look like being overshadowed by these events, and I expect many more to follow.
I no longer live in the UK but feedback from friends and relatives still there is that the coming vote is not just about Europe but about people getting a chance to show their thoughts on migration in general.