Who needs this? Mary Poppins in a bad neighbourhood?
But then I realized I'd rather just give someone my cell phone and wallet instead of a fight to the death with an umbrella..
You don't understand 'most perps'
Just run
a) People who want to discretely carry a weapon.
b) People who realize most umbrellas are hot garbage, and understand that an umbrella that won't break if you even stand on it are probably going to last a while.
But maybe others have had better luck?