I told her I was upset. I told her that going into my locked backyard without permission was not a misunderstanding. She replied that she had assumed our neighborly arrangement included reasonable flexibility. When I asked how the gate had been opened, she said she was not sure and that perhaps I had left it unlocked. That possibility was irritating precisely because I had no objective record disproving it. I knew I was careful, but my certainty about a latch was not the same as evidence about who had opened it.
I purchased a better gate lock that weekend. The hardware-store employee recommended a weather-resistant model with a protected shackle, and I installed it myself after reviewing the manufacturer's instructions twice. I put the key in a small envelope in my desk, where spare house keys lived. I was aware that this seemed unnecessarily formal for a fence gate, but by then I had discovered that informal arrangements become expensive when the other person treats informality as permission to invent new rules.
In late August, a small incident made the larger problem impossible to ignore. I returned from an appointment and found four strangers on my patio, two adults and two teenagers, with the sound of laughter coming from the pool. Sandra was not there. One of the adults told me she was a friend of Sandra's and that Sandra had said they could use the pool while she attended a school meeting. The woman seemed sincere, and her embarrassment was immediate when I explained that the property belonged to me and that I had authorized no such visit.
She apologized repeatedly. I felt sorry for her. She had accepted an invitation that sounded ordinary when it came from someone she trusted, and now she was standing in the backyard of a stranger who had every reason to be upset. I asked everyone to leave and gave them time to collect their belongings. The adult who had spoken to me offered her name and telephone number, saying she wanted to explain if I ever needed confirmation that Sandra had invited them. I wrote the details on the back of a receipt and put it in my desk.
I sent Sandra a message that afternoon. It was brief and specific: No one is to enter my backyard or use the pool without my express permission. You do not have permission to invite other people. She did not reply for several hours. When she finally did, she said she was sorry I had been surprised and that she thought we had a community-minded relationship. She added that children benefited from generosity and that she hoped I would not become "one of those neighbors who counts every little thing."
I was, unfortunately for her, already a neighbor who counted things. I was an accountant. Counting was not a threat; it was a basic professional skill. What I had not done was apply that skill to the number of times Sandra had crossed a line and then treated the crossing as proof the line no longer existed.