Why dont they just have an entry fee and have it open to ride year round?
Why don't you buy the property and do the same? I'm guessing because of insurance, security, ppl messing w/ their farm animals, ppl destroying the stage and other equipment the have out there for when they have events and concerts. They are not big fans of theft and w/o anyone out there things tend to have a 5 finger discount for some odd reason. They have a cattle business and they use that property during the week for the other business. Because there are fences and they don't want ppl tearing down their fences and riding on other sensitive lands. Because if/when that happened it would open the property to the government having issues w/ them. Because they don't feel like paying for someone to come out and pick up the trash that idiots leave behind. And the number one reason I'm sure they don't do this is because it's their property and they can do what they want and don't want to deal w/ the hassle of having ppl on it 24/7/365 unsupervised.
I'm sure many ppl would be happy to come play in a back yard any time they want and destroy someone else's property.