If you're dealing with youth, it may be a different story, but with adults, a solid briefing on risks, hazards, and dangers should be sufficient. After that, they'd have to prove negligence. For instance, if your field was covered in Bengal tiger traps, and real life land mines, then you could be in trouble. Reasonable danger is normal, but don't play in a grizzly mating habitat.
ďREALITY IS LIKE A STONE. TO MANY ITíS HARD AND COLD, THEY CANíT HUG IT OR EAT IT, IT ONLY FRUSTERATES THEM AND DOESNíT DO THEM MUCH GOOD. TO OTHERS ITíS STRONG AND DEPENDABLE, YOU CAN BUILD WITH IT, BUILD UPON IT, OR WORK WITH IT, ALSO USE IT TO SMASH PEOPLE IN THE FACE.Ē