I KNOW there must be lead in the paint at the house I bought. But do I want them to have it tested? No WAY! Because if they find that it has lead in it, it MUST be removed. Yes, at their expense - but that means they lose a ton of money on the sale - or they can't sell the house at all - to ANYONE until the problem is rectified. (I'm thinking of the seller here - not the buyer. The buyer loses by not being able to own the home they want because it contains a 'hazardous' material that is not really all that hazardous if dealt with properly.
I also know that the ductwork has asbestos tape at its seams. Likewise, I'm not asking to have it tested, because that just screws everyone. When I move in, I'm going to paint over it with special paint. As long as I don't mess with it, it will not be a hazard.
The best way for a homeowner to treat asbestos, if possible, is to encapsulate it so that the fibers can't become airborne. That is the most cost effective way, and it is completely acceptable.
Asbestos will not hurt anyone if it is not accessible.
And 'suspecting' that you MAY have a hazardous material in the house is much different from 'knowing' you have a hazardous material.