When I bought my farm, there was a one acre parcel out of the side of the 59+ acre piece. The story behind that is that bothy properties were bought on tax deeds back in the 1930s and the family I bought from had gotten most, but not all the deeds to make up the farm.
A local man who was a land speculator had the other acre - my piece surrounded it on three sides and a one hundred acre parcel was on the fourth. I offered to buy it, but the man turned down my offer. I guess he thought I would develop the land and he could sell it for more.
But I looked up the laws about providing access. If he sold it to someone who wanted to build a house, I had to let him drive through my property - I did not have to give an easement, but I had to allow access. I didn't have to make it easy - there could have been as many gates as I wanted between his acre and the county road and I could have insisted that each and every one be closed every time he passed through.
About 1989 the 100 acres was developed, which put a road much closer to his property - but they did not provide an easement, either so I am not sure if an owner of the acre could have been forced to get in and out that way.
In 1999 the land speculator, then in his late 80s, contacted me and offered to sell me the acre for the same price I had offered in 1978. I jumped on it!
I can see if the man in the OP story was careless about closing gates - or as the other property owner said, he was scaring her clients - she could be annoyed. But I do not see that she could cut off all access for the man. The stupidity I see is selling him a piece of land with no easement - that makes no sense.