What if....you went to the park one day to have your lunch only to find out that the park was fenced off and you no longer had access to it.  The reason being that someone else who takes their lunch to the park didn't have your consideration and left their garbage behind (I have this crazy notion that the homeless are not the only people in the world who litter).  This of course is not even considering if you had nothing else in the world besides that park - no where else to sleep etc.