As I travel the world I am frequently asked about the "gun culture" of the USA. I usually answer that except for acquaintances who hunt and an occasional trip to the range I don't really know much about it other than the right to arm oneself is burned into the American psyche.
As I read the most recent news about London it struck me that this could have happened in New York, LA, Chicago (where only gang members carry) or a number of other major cities in the US. All have taken intense steps to disarm their law abiding citizens. Since every major massacre in the US in recent history has taken place in a "gun free zone" this strategy seems to have major problems.
I don't know the right answer. But the fact is that there are thousands of these crazy people in Europe and the USA already. More border controls may keep more out but that is just closing the barn door after the horse is gone. I don't see "shelter in place" a viable strategy unless we change the architecture of our buildings.
One would think that sailing would extract oneself from the danger. But the truth is that many of the places we visit have similar problems.
Fair winds and following seas :)