​Previous pest inspections are an important factor when looking at a house to buy. Having received my statement of attainment for inspecting for and the reporting on timber pests, also the control of timber pests, I understand the processes that prior pest operators have applied.
Treating areas with pesticides, considering some of the older treatments were quite poisonous, it is important to understand why they were used as well as where.  Sometimes however the spray operator may have caused structural damage to the house, to make his job easier.
The home owner is never likely to crawl under the house, so short cuts are made to gain access and unless you employ a diligent house inspector, you too would never know. Until you suddenly have a structural failure of the flooring of the house you purchased.