Yeah, but an airfield isn't an attractive nuisance. They definitely make it very, very clear that YOU NO GO HERE. You can argue the implementation was bad, but I think both the implementation AND the lack of warning / clarity of badness has to be there to be actionable, to my meager knowledge. (i.e. the abandoned wood chipper? Sure, sue. An abandoned wood chipper behind a 6-foot high fence with DHS warnings? Nah, even if the fence is bypassable.)