You dont have to be in the military to get one of these http://www.addictedtopaintball.com/store-products-Grenades,-Landmines--Bazookas-Claymore-Mines-PBM14-The-PBM-14A1-SENTINEL-Mil-Sim-mine-is-a-claymore-style-mine._7438687.html
Im thinking a couple of these and the poison ivy trick should keep the hooligans away for a while.