Somehow because she used that land for so many years. She maintained the right to use it. It’s mind boggling to think about these dumb ass laws.
It happens all the time.
Just wait until you get into a situation where squatters move into your home/property. There is a time period you have to formally evict them before they have a right to be there. Happens with rental properties all the time.
Squatters' rights vary state to state, but when someone is using your property for a certain amount of time, they do have rights to it.
I've seen a case where a person had to pay a maintenance fee to his neighbor because the fence was 1-foot on his property. His neighbors had maintained and improved the landscaping to that 1-foot strip over a period of 15 years.
Another case an old man allowed a couple to setup a trailer on his property for like 20 years and when he went to try and remove them, the County granted the people rights to stay on that section of land. So, he couldn't sell it because that section of land became a shared access easement, and there was no way to access his tract anymore.
This is why you never let anyone use your property for any reason.