For those in areas where firearms are forbidden, a baseball bat or golf club might be illegal to carry in many places, but I would think that a metal or wooden cane or walking stick might pass muster. If a telescoping baton is allowed, that'd be ideal, because it can be carried on a belt or in a purse much more easily.
when confronted with multiple attackers your best defense is your back to the wall and a good rifle with 20-30 rd STANDARD capacity mags. A pistol if you can't have a rifle.
A good knife is a must. Preferably a fixed blade, Kbar being ideal but something more discreet may be desired for formal occasions.
Assisted openers are a good second choice.
And don't forget the flashlight.
All the martial arts training done with boots and gloves means nothing in an encounter with half a dozen crips, bloods or zetas that want your nice, new shiny SUV along with your wife and 2 teenaged daughters.
A friend of ours went to MOSCOW Russia, as a missionary. He was told to immediately go to a bicycle shop and buy a bicycle chain and keep it up his slieve, in case he is attacked by hoodlums, and to use it as a flail if attacked.
It was advise that came in handy on several occasions.