I think you have it a little backwards Newshawk.
Nielsen does extensive research on each market to determine where MOST of the people in the county work, do business and the way they spend their free time. Generally they look at which area they have more economic ties. In all but just a few cases the lines are drawn along the county lines. This means that in some cases, people on one side of a county may be included in the "wrong" TV market. It isn't that Nielsen is catering to anyone in particular. It is the fact that MOST people in that county have more economic ties to one market over another.
An example close to home here is Butler Co Ohio. The southern county line is only 20-some-odd miles from downtown Cincinnati and just under 20 miles from most of the transmission towers and home to two other TV towers. One a Butler County PBS station (Oxford), one a Richmond, IN station (TBN). The northern county line is within 5 miles of the Dayton, Oh antenna farm and 20 some-odd miles from downtown Dayton. What TV market is this county in?
Well... This county has three very large communities that are essentially part of the greater Cincinnati metro area (Fairfield, Hamilton which is the county seat and West Chester County). You ask anyone from these areas where they are from and many will say "Cincinnati" or mention their town name and say, "Near Cincinnati".
Middletown is just that, anything south of middletown is pretty much linked to Cincinnati. Anything north of Middletown (including MT) is linked to Dayton. The thing is that the northern part of the county is mostly rural. So it isn't even close. Most of the people in Butler county are economically linked to Cincinnati. So, the whole county belongs to the Cincinnati market. If you were to ask some one in Middletown, they'd say you were NUTS!
The same thing goes for Warren county. There are many, many large communities in this county that are part of the Greater Cinti area including the fastest growing city in Ohio, Mason. To the north....wheat and cattle. Again the population split to Dayton is not even close. But ask some one in Springboro or Carlisle and they will argue the county is in the wrong market. These people can litterally see the Dayton antenna farm from their back yards!
See ya
Tony