Investors, landlords and heirs will often try to not disclose any defects because they claim they never lived in the house. Occupying a house doesn't mean you the owner are not aware of it's condition and/or defects. Obviously, there might be some defects you are unaware of simply because it would require use. However, as the owner of the property, the odds of you not knowing anything about the property is slim to none. Did you ever pay a bill? Did you ever authorize a repair? Did the tenants notify you of concerns? Did a previous buyer notify you of defective items found on their home inspection? Did your predecessor ever discuss defective items with you? Hopefully, sellers are getting the point.
There are many cases where a seller simply does not know. In that case, disclose you don't know. Sometimes, sellers geniunely forget because it was so many years ago or are truly unaware. When it does come up, disclose it immediately in writing. In my experience, red flags go up when I see a seller complete a seller property disclosure that discloses nothing good, bad or otherwise and simply says 'never lived in property.' I immediately begin asking questions. Again, there are a few cases where this is true of the seller. However more often than not when I start prodding for information it becomes clear the seller does have information in regards to the structional, mechanical, and safety issues of the property or it's boundary lines.
A seller putting in writing the property's condition (disclosure) is a CYA for the seller. It is not a warranty of any kind to the buyer and a buyer should still be prudent to inspect/investigate any and all items pertaining to the property. Sellers please seek legal advice before determining whether or not you are going to disclose. Buyers, beware. A sellers property disclosure is only as good and informative as the person who wrote it so do not solely rely on it.