(WSJ) "Typically terrorism attacks spark an increase in travel insurance sales, but insurance experts caution that most policies offer limited protection. Most policies only cover you if the attack is in or near a city that’s on your itinerary and within seven to 30 days of your trip. If you want to cancel a trip to London or Paris because of the Brussels bombings, your insurance likely won’t cover you. And any policy purchased after government alerts are issued won’t cover known threats.
“Unfortunately, the threat of terrorism is not enough to trigger a policy’s terrorism coverage,” says Adam Rusin, product manager at Squaremouth, a travel insurance comparison shopping site.
The best insurance if you think you might be afraid to go is “cancel for any reason” coverage, which is more expensive but more useful."