Family Friendly?

Joe and I took the kids to the park this afternoon for some free time.  When we got to the park, the older boys took off for the playground equipment while Joe and I headed for a bench swing with Micah.  As soon as I sat down I smelled a rather peculiar odor, but said nothing about it.  Joe sat down next to us, looked down at his feet and said, "Tell me that is not what I think it is." 

I looked down and sure enough the ground all around our feet was covered with dried green herbs that definitely were not oregano or parsley.  Obviously someone had spilled their baggie full of marijuana on the ground and was either in a hurry to escape or was too stoned to realize what had happened.
Joe started kicking at the ground (to try and cover it up with sand) which only intensified the smell and got it all in his work boots and my shoes. Noah of course chose that moment to walk over and ask what we were doing.

I am furious that I even had to come up with an answer to that question.  I mean, we were in the park for crying out loud...a children's park with playgrounds.  What has happened to our society that someone would think it was acceptable to go to a public children's park to smoke their weed?
Or maybe it was someone selling there and dropped their stash.  That makes me even angrier.  What chance do our children have if they are finding drugs on the playground at six years old?

Is there nowhere left that is family friendly?  Do I have to keep my children in the house all the time in order to keep them from being subjected to drugs, alcohol, foul language, and sexual perversion?  I know that at some point in thier lives they will  have to face all of those things, but at six years old they should only be worried about which swing to swing on, not what the green stuff is all over Daddy's shoes.