The fact that the injured party is trespassing doesn't amount ti a hill of beans when it comes to lawsuits. There was a former gravel pit that was no longer operating. The owners did what they could to secure the property and it was signed, but virtually every weekend, the masses on ATV's, dirt bikes etc, swarmed there.
The owners, THOUGHT, they had done their due diligence. But it was well known, that people were in there riding. Then one sad day, an incident occurred, the rider died. The family sued. They won, the judge ruled that although the rider was indeed trespassing, the owners didn't take enough steps to secure the property, and given that it was well known as a place to ride, the owners certainly also had to be aware of this, and as such they had a duty to secure the land, be it better fencing/walls, security, etc. but simply putting a fence, (which people tore down to ride), and signs were not sufficient.
They lost millions. they now have better fencing and have the regional police attend, virtually every weekend with the authority to charge ANYONE found to be on the property. It is a crap show when the police arrive as people scramble in every direction to avoid charges. Been ongoing for many many years.
Try riding the OPG property out towards Port Hope. The trash and dumping of stolen vehicles, and OPG had enough AND didn't want the Liability. The OPP now regularly attend, and advise people unloading to load up and get out. They advise they have recorded plates if at ANY time the return and the plate is seen and an empty trailer you get a summons in the mail. Mostly local ATV'ers. It takes a few to ruin it for everyone.
OP. It doesn't matter HOW good of friends you THINK they are. As someone has pointed out, a SERIOUS incident, resulting in a "buddy" no longer being able to provide for his family, either because of a life altering injury, or death. Not only WILL that "buddy" but so will his family, (wife and kids, plus parents etc), be quickly convinced by an ambulance chaser there is MILLIONS to be had. You and your family, will NEVER again own ANYTHING of substance, including a house, bikes, vehicles. Despite what some have asserted, this will happen if you design and build a "track" you need NOT build anything, just merely an invite to do an inherently dangerous activity, (riding a bike or ATV etc), would qualify as such an activity.
Just call your insurance agent/broker and ask for a quote. IF they stop laughing long enough, by the time the risk management people get done coming up with a quote, you WILL quickly decide against it.
The one that comes with the package they send you when you apply for a sanctioned event.
My only experience is with CMA sanctioned events.
The absolute ideal circumstance from a land owner perspective, is when the rider in question is trespassing.