This is annoying. It's not like the Common is some manicured spot, like the Public Gardens. It's supposed to be for people to USE, not to be walled off with "no walking on grass" signs. And it's for everyone, it is not someone's personal front yard. Sorry, but these people knowingly moved into an apartment with a known nuisance across the street. I feel no sympathy for them.
With dirt and grass underneath on the Common, people attending large events like Hemp Fest or the post-Gay Pride parade festival can sit down, spread a blanket, lay out in the sun, toss a frisbee, spend some time and socialize. CHP is not at all comfortable unless you carry along a rickety lawn chair and people without planning like that will probably only stay for a short period of time.