Union Square Aggression

I was warned that begging for money was prevalent in San Francisco but I never expected it to be so invasive. I tend to avoid Union Square and frankly, have only been there twice since I moved here -- and never at night, until recently. I couldn't walk two blocks without people aggressively asking for money. By the time I reached my car, we had encountered close to ten people, who wouldn't move out of our path until we gave in or darted for cover - my car. And when we didn't oblige 9 out of the 10 cases, they simply did not go away. Intense. I've lived in a lot of places, but never quite experienced this level of aggression among the homeless.