For instance, an NDA seeking to restrict an employee forever from applying all skills he acquired in a workplace after leaving that employment may not be considered reasonable.Types of NDANDAs may be unilateral or bilateral/mutual or multilateral.In unilateral NDAS, only one party receives information from the other party and the former bears the obligation to safeguard such information.

You really want to make sure that the land you are buying doesn't have any major constraints that can't be overcome, or even if they can be remediated, at what cost, i.e. environmental, soils/geotechnical, adequate access, zoning, etc. 

How much risk are they willing to bear?

If you can't get sewer, then your alternative is onsite septic, if soil is suitable, then your buildable area shrinks dramatically due to drain field and reserve areas for each home.

I use a binding arbitration clause with each party to bear their own costs.  

It is required to have a building permit/inspection and hire licensed professionals for Electrical, Mechanical, Plumbing, and structural engineering for load bearing, gas line work, and septic systems. 

They may have to remove 5 tons of soil , they may have to remove 50 tons .

Pictures and listing text won't show you a failing roof, soil pipe, wet basement that is currently dry, etc.

Note that I don't have a material interest in supporting either the bull or bear narrative. 

They bear the responsibility to pay you (again).Now, it's also on them to raise the issue with Police/USPS IG and get that investigated but work it out with them by tacking on a payment plan over say two years?