Park eating area minus the inebriated

The town that I used to live in had a park with a gazebo/eating area and park stuff in it. It was usually okay during the day, but some days, we'd find that the local drunks had been there the night before and sent their anti-blessings on it. So what I want is some form of protection that could work at night, either a fence or some form of fiendish obstacle course that would work as a childrens playground by day, and protect the park at night by those who've had one for the road, one for their health, one for their uncle.... [later] okay, the revised edition, ie, how this thing shall work: I just have to add the moat (thanks for the idea, wagster), plus the revolving thing (david_scotherns' idea), except the stairs revolve with it, so during the night, at a set time, the stairs revolve to the other side, which will probably foil some of the jolly drunkmen, and the moat will be probably knee-high deep with a fence surrounding it to stop small kids falling in, drowning, and the local council getting sued. Is that detailed enough? [even later] The drunks that get caught have to pay a fiver (in local currency to get out. Sorry, but no Marios, I think the super-hero-plumber business has gone into decline...