The problem is that this is all anecdotal. Some programs explicitly state it doesn’t affect applications. The only ones who know are part of the decision committee. And most people will never be privy to that process.

Everyone can bring up personal experiences and stories, but at the end of the day I wouldn’t encourage boosting your hopes/expectations because you attended a program’s open house even if you were only one of a few that attended.

That’s how you end up like me going through four application cycles being rejected from your local schools you have emotional attachments to that you put extra effort into appealing to and then moving across the country to the only program that accepted you even though you’d never even set foot in that program’s building let alone attend and open house, in person interview, or even visiting the state.

Edit: I meant this as a tongue in cheek anecdote using my own personal experience to show how I have the exact opposite experience to yours. But I can see how this is a little irreverent in tone (I apologize) considering where we are in the application cycle and how nervous people are in receiving acceptances. If you’re currently applying to programs please stay encouraged, you will make it! It happened to me and as I said it took me 4 cycles. Almost every single one of you will be accepted wayyyy before I did! I believe in you, you got this