Well.....yes and no. Any buyer needs to go forth with the knowledge that it is a cold, hard fact that NO ONE ELSE is going to be there to protect you in an arms length transaction. You as the buyer must bear this responsibility alone. The idea that a seller is just going to jump up and voluntarily tell you everything about a used item, what's right or wrong with it and make this full honest disclosure every time is a pipe dream. I am not condoning this kind of seller, and it would be fantastic if everyone did this and was totally honest and up front, but there is a less than zero chance it is going to happen....ever. So, the buyer must ask the right questions and proceed carefully, or regret it. It's just that simple.
It's one thing if we are talking about a brand new unused item, but most of this stuff is used and the seller did not manufacture it. He has a used item for sale, often times not used by him, if you agree to buy it then it's yours and you own it. No one else owes you anything in regards to a used item unless some sort of agreement takes place in advance. Failure to disclose is not fraud, especially if the seller doesn't know there's an issue, and this and every arms length transaction absolutely is a matter of buyer beware. If you choose to not beware then again, you will regret it sooner or later. If you choose to not beware because you think some seller or some one else should do it for you then you are heading for trouble.
I believe that a seller should absolutely honestly answer any and all questions from the buyer, this is just a matter of being honest and those sellers that are not honest are usually not selling things for long.