try terrorist attacks bruce in Paris and the UK recently the last 12 months deaths galore unfortunately!
Thankfully terrorist attacks are very rare events Joe. Consider this - http://voxeu.org/article/trade-costs-border-controls-schengen-area
"overall goods and services trade of EU28 countries declines, on average, by 4.2%, relative to the status quo in 2011; this corresponds to an annual decline in trade volumes of €221.34 billion compared to a counterfactual situation without any border controls imposed within the Schengen area."
In other words, reinstating border controls within the EU would cost the member states €221 billion in lost trade alone, aside from the cost in time and productivity of people waiting at border controls.
You might argue you can't put a price on a human life, but that's a pretty hefty one imo. I've argued before, and I'll argue again, the free movement of people within the EU is one of the greatest political achievements of the last 100 years and it saddens me enormously to be walking away from it.