Don, those type of vests are often referred to as "Shoot-Me-First" vests as many UC LEO's and federal agents wear them as a way to conceal their weapon. If someone with some tactical knowledge were to start shooting, guys with vests may get it first as it's a good as wearing a badge around your neck in many places.
I know they are such an attention grabber that at least one federal agency does not allow their agents to wear them overseas.
It's akin to a guy wearing his combat boots on an airplane. Or some guy traveling with molle-covered backpacks.