Not everyone is equipped to fight it out with robbers, so this is good advice.
My mother was 70 when a street thug threatened her. She handed him her purse with her Social Security check in it without a second thought and he kept running down the street, leaving her unscathed. She was a mouthy lady, we were all so relieved that she did the sensible thing, thereby saving herself injury or worse.
I'm glad your mom was okay -- it sounds like she handled that situation just right.