How dangerous? Incredibly. That's why a minister of a country experienced a lot about that knows how to get faster to his gate (Blitzkrieg):

NATO to set up Schengen system for military, German minister says

NATO wants to set up a system to ease military movements across Europe, akin to the Schengen border-free system for people travelling across the continent, said German Defense Minister Ursula von der Leyen.

"We want to establish something like a military Schengen within Europe, that can move [troops] quickly and straightforwardly, without great bureaucracy, with great speed," von der Leyen said ahead of a meeting with her NATO counterparts in a two-day meeting in Brussels, DPA reported yesterday.

Germany has offered to host the command center for this, she added, noting that the country is "not only geographically in the heart of Europe, but also has great experience in logistics and support."

https://www.dailysabah.com/europe/20...-minister-says