I have to admit, I've never heard about any good "hard" proof of haunting at the Winchester House. It's one of those places that's so zany, you have to wonder if the simple bad Feng Shui of all the dead end rooms on this mansion causes the extremely uncomfortable feelings people get inside of it.
Here's how this "famous" haunted place scores:
1. Older than 50 years.
2. Sarah Winchester died in her sleep there.
3. The ground is sedimentary.
The fact is, the house is frame construction (incompatible with haunting), there are no waterways or railroad tracks nearby.
It will be interesting to use this one in my research to compare the score 3/6 (on the weak side of 3) with the actual "hard" proof of haunting that anyone's accrued. As it stands, with this borderline 2/3 score, I'd put it at "it's not ever going to be haunted, or it would take extraordinary events and time to make it haunted." I don't hold out hope it'll ever truly be haunted.