A seller's disclosure isn't worth the paper it's printed on. That's not me being cynical, or saying that sellers lie, it's just the truth.
A while back, I was talking to a potential seller, who happened to be a little bit older. I noticed the roof had some curling shingles around the edges, so I asked her if she knew how old it was. She told me it was replaced (which I took to mean a full tear-off) 2-3 years ago by 'Smith' Roofing. Since I happen to know the owner of that company, and thought the shingles looked older than that from the ground, I gave the roofer a call. He had to dig back a bit, but found out they had done the job 7 years ago, and it wasn't a tear-off when they did it, meaning the next one would have to be, and probably sooner than later (in Western New York.)
Now, I could assume Mrs. Seller was lying to me, or I could assume she just forgot when she had it done. I find that as I get older, it becomes a lot more likely that I would make the same mistake concerning the passage of time. The same came be said of water heaters and furnaces (check the dates on them!) and everything else concerning the house.
The idea of using an inspector is a good one, but it isn't foolproof either. The first house I ever bought, I had the inspection done by a local professional outfit that all the local realtors recommended. The inspector missed a couple of huge issues, which wound up costing me a lot of extra money, and worse, time.
Somewhere down the line, the previous owners, strapped for cash, knew the roof needed replacement. There was already a third layer on, which may have been acceptable at the time, but was not allowed by the time they went to replace it. The roofer they hired, rather than do the tear-off (which they couldn't afford) nailed new drip edge on top of the third layer of shingles, all the way around the roof, then put a 4th layer on, effectively hiding the 3 layers of shingle underneath. The next roofer to come along saw drip edge and a single layer of shingles, so he put on another layer of shingles, meaning that when I bought the house it had 5 layers of shingles on it, which were all completely shot. Even worse, walking on the roof felt solid, because apparently 5 layers of shingles nailed together can hide some pretty serious structural issues.
So when the roof finally came off, I not only had 5 layers of shingles on both the house and attached garage (21 square in total) I wound up having to re-deck the entire house, and fix a cracked roof truss.
Thank God I did it myself with some hired help, or I would have been looking at a $13,000-$15,000 job, easy.
Additionally, the house was originally wired with Aluminum wire, which may or may not be the worst thing in the world, depending on the electrician you talk to. One of the previous owners decided to 'fix' this by rewiring the house. Unfortunately, they ran 14/2 wire from every outlet in a room to a (not to code) junction box above the rooms, wire-nutted everything together in the box, and cut off all of the ground wires both in the outlet boxes and junction boxes. So nothing in the entire house was grounded properly, meaning I had to rewire the entire house.
Both of these issues were missed by the inspector, and may have been missed by many inspectors, but will never be missed by me again - that's for sure. And the previous owners may, or may not, have known about any or all of them - but none of it was on the disclosure, nor would I expect it to be.
Even if they knew, proving it is a whole 'nother deal.