From the article (I would have had the same reaction - all I would have thought of was the "Taxi Driver" scene where Travis Bickle shows up in a Mohawk):
"A customer in the parking lot of the Walmart observed the defendant putting on his body armor and then sling the rifle across his front while recording. Based upon his actions and recent events, she feared for the people inside the Walmart and had her boyfriend call 911. She has never been bothered by people carrying guns in Walmart before but this was different.The manager of the store is familiar with individuals carrying openly in his store,but also stated this was different."