Do you treat your butler's reports of visitors as complete and reliable? If so, you might want to re-think that. Here's a case in point:
Today I saved my logs covering a period of about six hours and spanning three game days. During that time, while I was in-game, my butler informed me via IM of 8 people visiting my street. At the end of that period, I used the "Who visited?" feature to get a list of visitors. The list I got from my butler in this manner included only 6 of the 8 people the butler had told me about via IM. There was nothing special I could see about the two players who were not included in the list. In particular, they were neither the first nor the last visitors during the six-hour period in question.
Based on this and other observations I've made about my butler's reports of visitors, I conclude:
1. Butlers try to remember and report everyone who has visited since the the past time they were asked "Who visited?"
2. In spite of their best efforts, butlers sometimes leave people out of the list.
3. Butlers are particularly likely to leave some people out if there were a lot of visitors.
4. However, butlers also can leave people out even if there were not many visitors.
5. People can be left out of the "Who visited?" list even if they visited recently.
6. People can be included in the list even if multiple game days have passed since their visit.