I wouldn't risk it. I am not talking about your own liability, or your personal security, or the safety of anyone who might wander by your game. I would not risk the integrity of the sport. Paintball is still a relatively new sport, under a lot of scrutiny from the public and everyone has to make sure this sport does not earn a permanent reputation as a game for miscreants or lawbreakers. People need to see it as a sport played by polite professional athletes who are boons to their communities. It does not take a genius to imagine how a small accident normally handled by an insured field, can spiral out of control. God save us all when the media gets a hold of that. It may seem like its secluded, and you may successfully play there a dozen times, but only one mistake has to happen. It can be as little as an old person walking by and calling the police on "trespassers with firearms" and it could be as serious as an aggravated injury to a player or bystander.
Private paintball is doable. Just please don't take this kind of risk for the benefit of the sport. Play on private property with regulated safety equipment.