It only takes a second for a purse snatcher, I'm guessing someone handicapped may be in a wheelchair or walking with a walker/crutches so they wouldn't be able to hang on to a purse.
I was walking out of a hardware store so I was near the door in plain site around lunch time and a guy walking toward the store stopped at a truck with a toolbox in the back, popped open the tool box and looked inside then closed it and continued to walk to the store. I yelled, was that your property and he flipped me off and kept on walking so me being there didn't stop his attempted theft.
When I worked retail in college I would push in carts from the parking lot. People would drive down an isle and a couple kids would hop out and walk across the rows of cars checking for unlocked door handles the meet the driver a few isles over and get back in and drive off. I gave several license plate numbers to the security people in the store.