>But how to cope with such a danger clearly visible? Pin the electronic equivalent of a yellow star on them? Probably refugees would not object, but from historic POV hard to argue for over here. Create a vetting network here? Should be possible to at least start quickly and with swarm idea might actually be helpful using pictures of those going through official entry points, but within a few weeks terrorists would avoid official entry. Spying on own population also has bad aftertaste from WWII and east german times
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>You have a point. However, I am curious - how many refugees have the Muslim countries of Saudi Arabia, Turkey, etc accepted?

Last figures I've seen:

1.9 million in Turkey.
1.1 million in Lebanon,
250k in Iraq
142k in Egypt

OTOH, Qatar,UAE, Saudi Arabia, Kuwait and Bahrain have accepted none.

EU total is about 184K. Germany has accepted the most (47k), UK the least (14k)

U.S. appears to be ready to accept a measly 10K