While I don't disagree with Hastings advice, I'm not sure how seeing a robber with a shotgun comming at you and dialing 9-1-1 is going to be a big help in that particular situation.Hastings did offer some tips on how to get out of an aggravated robbery situation safely. He says above all, be aware of your surroundings--and if you notice anything suspicious, contact police by calling 9-1-1.
A carry gun is much better. And a vest wouldn't have hurt either.
Richard Davis invented kevlar vests for just such occasions as this one:
"The concept for Second Chance® soft concealable body armor was conceived in a dark alley on Detroit’s far west side on a summer night over a quarter century ago. Richard Davis, owner of a small local pizzeria, was making a delivery when he was attacked and shot. Davis returned fire wounding two of his three attackers. Weeks later while recovering from his wounds, Davis' business was burned to the ground.
The ‘69 shooting incident inspired Davis to research and develop a means of personal ballistic protection. The result was a soft, flexible, concealable panel of ballistic nylon material layered to stop common street handgun firepower. The ballistic material, first generation in the body armor industry, was similar to that found in flak jackets worn in Korea and Vietnam. By taking the bullet resistant panel, large enough to protect the wearer’s vital organ area both front and back, and placing it under an outer garment hidden from a possible assailant, the wearer was given a "second chance" to survive a ballistic attack and retaliate.
...
During the ‘70’s, Davis experimented with many kinds of ballistic material, finding DuPont Kevlar® to be the best. "
http://www.secondchance.com/information/history.htm