He argued that all force used to protect oneself or one's belongings should be considered reasonable.

BBC: Peers call for clarification of self-defence laws

While it is impossible to predict a terrorist attack, taking some precautions and preparing oneself should be a priority for all travelers, says Christopher Falkenberg, a former Secret Service agent who now runs Insite Security, a risk management and security consulting firm that services corporations and high-net worth families.

FORBES: 10 Secret Service Survival Tips for Travelers