Laws are there but prosecutors are sometimes loath to enforce them. To wit, Ross Mirkarimi had to draw up a new sit-lie law to address the nuisance of intoxica

Laws are there but prosecutors are sometimes loath to enforce them. To wit, Ross Mirkarimi had to draw up a new sit-lie law to address the nuisance of intoxicated kids blocking access to businesses and housing. But we had plenty of laws already! It wasn't a problem in the 60s and 70s, or even 80s. But come the 90s, oh noes, we can't enforce them... so we have to draw up new ones...