Who Gives a Shit: Are We All Gonna Get Stabbed by Roving Gangs?

So, some concerned citizen/neighborhood watch member/paranoid old crank is going around posting notes on the doors of apartment buildings along Prospect Park West, warning people about the increased activity of roving gangs in the area by the park.

I wish I had saved the note, or taken a picture of it with my shitty iPhone camera even though it would be unreadable anyway, but it basically said:

1. Teen hoodlums are coming to get you
2. Srsly, someone got stabbed
3. Call 911 and remain alert

We all know that the park is a place where delinquents tend to hang out, especially with it's proximity to the subway and the Pavilion, but this is New York, so I try not to characterize every person in a baggy sweatshirt with a backwards baseball hat on (with the sticker still on it!  Very important, apparently.  I learned that by watching MTV Cribs, Lil Bow Wow edition) as a potential threat.

Of course, this was before my friend got jumped at 3:30 in the afternoon after walking home from a school in Bed Stuy where he was teaching, prompting me to send the following insensitive ecard:

 
So, I really do appreciate the anonymous letter-writer's head's up (and the brilliant suggestion that I should call 911 if I see a crime—never would have thought of that), but I really can't tell if the person/people behind this note are just overreacting, or if it's actually a real problem. 

So, what do you guys think? Are you seriously worried about roving gangs in Park Slope?