Frisco is a name that was used by people living outside of San Francisco, they chose to use it as a shorter way of saying San Francisco. Today people in Rap, or those that families did not originate from San Francisco call it "Frisco".
Most of today's residents of San Francisco are not true San Franciscan's but claim San Francisco not truly knowing the history or having any real legitimate ties to San Francisco.
Sco was a nickname given by rappers to San Francisco.
" i'm headed out tonite"
"where too?"
"Frisco, they got plenty of freaks"
Term used to identify recent arrivals to upper class areas in San Francisco nervous that they don't fit in.
Do they freak out and correct you when you use it? You've found a newbie.
Bob: "Nice weather for Frisco"
Bill: "Never call it Frisco! It's an insult! Only people that aren't from around here use the term!"
Bob: "How long have you lived here?"
Bill: "Three years. More than enough to be a local."