Sadly, the program this week slipped back to where it started.
The first story concerned a query as to whether a Canadian's McAdam ancestors were related to royalty, and evolved to whether there was a relationship to John Louden McAdam, who devised "a simple and economical system of construction which brought speed, efficiency, and comfort to the roads," and became the modern tarmac road. In attempting to establish the relationship the program relied on the IGI.
The researcher turned to Burke's Peerage to eliminate any linkage to royalty, then to the International Genealogical Index (IGI) to examine the link to John L McAdam. The IGI is a finding aid, not a definitive source. Were the Scottish Old Parochial Records not searched? Perhaps they yielded nothing; probably not good television. But to accept the IGI, especially entries based on patron submissions, and then turn speculation that two people of the same last name living 11 Km apart in the IGI into a relationship to be celebrated is not good genealogical practice.
According to the Dictionary of National Biography "McAdam, John Loudon (1756–1836), builder and administrator of roads, was born in the west-coast town of Ayr ... on 21 September 1756. .... His father was a minor laird and his mother a niece of the seventh earl of Dundonald ..." So if you're going to accept the tenuous link of the IGI then you may as well go all the way and claim a link, if not to royalty, at least to Scottish nobility ... and all the benefits that go with it.