Do neighbors have prescriptive rights to our property?

We purchased our 3 acre parcel of property 6 years ago in California. The property borders up to a local school. We began building our home 4 years ago and have resided here for 1 year. Children and neighbors have been walking through this wooded 3 acres for about the last 20-30 years to get to the school. After we purchased the property and began construction of our home, we paved the dirt path & fenced it with intent to donate it to either the City or School. We didn't want the liability. It turned out that neither of them wanted the liability either so we gated the pathway off with locked gates and "private property" signs. Although this portion of our property is blocked off now from the public, there is another way around to the school which is approximately 5 minutes on foot. The gates went up about a month and a half ago and there are some neighbors upset that feel they have a prescriptive right to this portion of our property. We are not sure yet if they will sue for it, but chances are they may. I read that one of the criteria for determining prescriptive rights to use of property is "without significant objection or bona fide attempts by the owner to prevent of halt such use." Would all of our attempts which began 2 years ago to give it to the City or School fill this category? We made numerous attempts, even after rejections, to give it to both. The only permission we ever granted was to the school about 2 years ago. It was during one of our phone calls when we tried again to donate the path. When they said they didn't want the pathway, we advised that their children could still use it for the time being. I'm trying to determine if we are sued, if we have any chance. Should we pay for all the legal defense costs or just reopen that portion of our property to the public. We just don't want the liability associated it. There were numerous motorcycles racing all hours of day & night, dog fights, etc. Please help. Any info would be greatly appreciated.