Yup, exactly. That's what they're up against. I think it's reasonable to take precautions.

I guess I'm getting downvoted for "checking ID at the gate doesn't prevent you from flying your airplane into the building" which is true, but we have to realize that most anti-government-inclined folks don't jump right to a terrorist attack as their first intervention. I do think that people hired to do a job deserve some protection from the general public while at their workplace.