i have had similar problems with my house.
my town re assesses every other year. they also want to inspect every house after it has been sold to make sure nothing was done without getting a permit so they can fine the old owner of the property. if you don't let them inspect you will be responsible for any work done without getting a permit. most of the time this is done before you move in so the inspection is rarely refused.
Zillow list my house at 2800 sq ft and estimates it's value at $395K. it's actually 1800 sq ft and according to recent sales it's worth about $250K. i only paid $75K for the place.
i have had to protest the assessment every year for the last 10 years since i bought the place. after the second year i had the assessor give me a copy of his assessment stating my house is only 1800sq ft. now when i protest the assessment i just include a copy of the copy stating my house is 1800sq ft and they re figure my value without even having to talk to anybody.


on another note.
i am sure just as many rich conservatives as rich liberals buy houses, knock them down and build Mc Mansions.