That they stated in the article they thought people would approach them for conversation while carrying ARs is an indicator that they didn't think this through very well.
And this demonstrates the usual bi polar nature of thought among OC activists and many Gun rights folks. They can believe to distinct and opposite things are equally true.
On one hand they maintain that the world is a far to dangerous place to go unarmed. There are people out there that want to hurt you. They also maintain that OC is an effective deterrent against criminals.
But then they equally believe that other citizens should not be alarmed by unknown individuals openly displaying firearms or even carrying rifle in their hands.
Apparently these people are NOT supposed to believe that there are people out there wanting to hurt them and the sight of an unknown person with a firearm is not supposed to disturb them at all.