Yeah, you're probably right, but then again, who would expect them to do the same thing again? This one might have been a slow leftover from the "airplane" days, but ya never know. I guess that we just have to remember that there are enemies out there that will do anything to hurt the people of this country. Including those methods tried before. They'll pick the easiest and/or least likely means of causing trouble. We just have to eliminate the easy ones and watch for the really unexpected.
We must be vigilant and watch all avenues of attack. Its not an easy task, but I wouldn't dwell on the dangers to the point of not enjoying life either. Just keep an eye open. We as a country have been a little lax on keeping our eyes open of late, I'd say.
DOGS, is all I can think to catch the rest. Every ship, every container needs a cursory check.