I can't talk about the Goulburn incident, but there are a vast number of private weather stations that feed into WUnderground. If you look at them, you will see definite trends across fairly small areas. Local microclimates can play a very big part in climate records.
There have been occasions where massive uproar amongst climate deniers has been caused after temperature corrections have been applied to a data set where the recording station has been moved. Moving a recording station then correcting the temperature bias is sound science, not a conspiracy.